2 # For a description of the syntax of this configuration file,
3 # see extra/config/Kconfig-language.txt
6 mainmenu "uClibc-ng $VERSION C Library Configuration"
8 config DESIRED_TARGET_ARCH
17 prompt "Target Architecture"
18 default TARGET_alpha if DESIRED_TARGET_ARCH = "alpha"
19 default TARGET_arc if DESIRED_TARGET_ARCH = "arc"
20 default TARGET_arm if DESIRED_TARGET_ARCH = "arm"
21 default TARGET_avr32 if DESIRED_TARGET_ARCH = "avr32"
22 default TARGET_bfin if DESIRED_TARGET_ARCH = "bfin"
23 default TARGET_cris if DESIRED_TARGET_ARCH = "cris"
24 default TARGET_frv if DESIRED_TARGET_ARCH = "frv"
25 default TARGET_h8300 if DESIRED_TARGET_ARCH = "h8300"
26 default TARGET_hppa if DESIRED_TARGET_ARCH = "hppa"
27 default TARGET_i386 if DESIRED_TARGET_ARCH = "i386"
28 default TARGET_ia64 if DESIRED_TARGET_ARCH = "ia64"
29 default TARGET_lm32 if DESIRED_TARGET_ARCH = "lm32"
30 default TARGET_m68k if DESIRED_TARGET_ARCH = "m68k"
31 default TARGET_metag if DESIRED_TARGET_ARCH = "metag"
32 default TARGET_microblaze if DESIRED_TARGET_ARCH = "microblaze"
33 default TARGET_mips if DESIRED_TARGET_ARCH = "mips"
34 default TARGET_nds32 if DESIRED_TARGET_ARCH = "nds32"
35 default TARGET_nios2 if DESIRED_TARGET_ARCH = "nios2"
36 default TARGET_or1k if DESIRED_TARGET_ARCH = "or1k"
37 default TARGET_powerpc if DESIRED_TARGET_ARCH = "powerpc"
38 default TARGET_sh if DESIRED_TARGET_ARCH = "sh"
39 default TARGET_sparc if DESIRED_TARGET_ARCH = "sparc"
40 default TARGET_x86_64 if DESIRED_TARGET_ARCH = "x86_64"
41 default TARGET_xtensa if DESIRED_TARGET_ARCH = "xtensa"
43 The architecture of your target.
60 # someone could sync this tree:
61 # http://linux-c6x.org/git/?p=uClibc.git;a=summary
92 config TARGET_microblaze
107 config TARGET_powerpc
125 menu "Target Architecture Features and Options"
128 source "extra/Configs/Config.alpha"
132 source "extra/Configs/Config.arm"
136 source "extra/Configs/Config.avr32"
140 source "extra/Configs/Config.bfin"
144 source "extra/Configs/Config.cris"
148 source "extra/Configs/Config.frv"
152 source "extra/Configs/Config.h8300"
156 source "extra/Configs/Config.hppa"
160 source "extra/Configs/Config.i386"
164 source "extra/Configs/Config.ia64"
168 source "extra/Configs/Config.lm32"
172 source "extra/Configs/Config.m68k"
176 source "extra/Configs/Config.metag"
180 source "extra/Configs/Config.nds32"
184 source "extra/Configs/Config.nios2"
188 source "extra/Configs/Config.microblaze"
192 source "extra/Configs/Config.mips"
196 source "extra/Configs/Config.or1k"
200 source "extra/Configs/Config.powerpc"
204 source "extra/Configs/Config.sh"
208 source "extra/Configs/Config.sparc"
212 source "extra/Configs/Config.x86_64"
216 source "extra/Configs/Config.xtensa"
220 source "extra/Configs/Config.c6x"
224 source "extra/Configs/Config.arc"
227 config TARGET_SUBARCH
229 default "e500" if CONFIG_E500
230 default "classic" if CONFIG_CLASSIC
231 default "sh4" if CONFIG_SH4
232 default "sh4" if CONFIG_SH4A
233 default "" if CONFIG_386
234 default "i486" if CONFIG_486
235 default "i586" if CONFIG_586
236 default "i686" if CONFIG_686
237 default "arcv2" if CONFIG_ARC_CPU_HS
240 source "extra/Configs/Config.in.arch"
244 menu "General Library Settings"
250 bool "Generate only Position Independent Code (PIC)"
252 depends on !HAVE_NO_PIC
254 If you wish to build all of uClibc as PIC objects, then answer Y here.
255 If you are unsure, then you should answer N.
257 config ARCH_HAS_NO_SHARED
260 config ARCH_HAS_NO_LDSO
262 select ARCH_HAS_NO_SHARED
264 config ARCH_HAS_UCONTEXT
268 bool "Enable shared libraries"
269 depends on !ARCH_HAS_NO_SHARED
272 If you wish to build uClibc with support for shared libraries then
273 answer Y here. If you only want to build uClibc as a static library,
276 config FORCE_SHAREABLE_TEXT_SEGMENTS
277 bool "Only load shared libraries which can share their text segment"
278 depends on HAVE_SHARED
281 If you answer Y here, the uClibc native shared library loader will
282 only load shared libraries, which do not need to modify any
283 non-writable segments. These libraries haven't set the DT_TEXTREL
284 tag in the dynamic section (==> objdump).
285 All your libraries must be compiled with -fPIC or -fpic, and all
286 assembler function must be written as position independent code (PIC).
287 Enabling this option will make uClibc's shared library loader a
288 little bit smaller and guarantee that no memory will be wasted by
289 badly coded shared libraries.
291 config LDSO_LDD_SUPPORT
292 bool "Native 'ldd' support"
293 depends on HAVE_SHARED
296 Enable all the code needed to support traditional ldd,
297 which executes the shared library loader to resolve all dependencies
298 and then provide a list of shared libraries that are required for an
299 application to function. Disabling this option will make uClibc's
300 shared library loader a little bit smaller.
301 Most people will answer Y.
303 config LDSO_CACHE_SUPPORT
304 bool "Enable library loader cache (ld.so.conf)"
305 depends on HAVE_SHARED
308 Enable this to make use of /etc/ld.so.conf, the shared library loader
309 cache configuration file to support for non-standard library paths.
310 After updating this file, it is necessary to run 'ldconfig' to update
311 the /etc/ld.so.cache shared library loader cache file.
313 config LDSO_PRELOAD_ENV_SUPPORT
314 bool "Enable library loader LD_PRELOAD environment"
315 depends on HAVE_SHARED
318 Enable this to make use of LD_PRELOAD environment variable.
319 A whitespace-separated list of additional, user-specified, ELF shared
320 libraries to be loaded before all others. This can be used to
321 selectively override functions in other shared libraries. For
322 set-user-ID/set-group-ID ELF binaries, only libraries in the standard
323 search directories that are also set-user-ID will be loaded.
325 config LDSO_PRELOAD_FILE_SUPPORT
326 bool "Enable library loader preload file (ld.so.preload)"
327 depends on HAVE_SHARED
329 Enable this to make use of /etc/ld.so.preload. This file contains a
330 whitespace separated list of shared libraries to be loaded before
333 config LDSO_BASE_FILENAME
334 string "Shared library loader naming prefix"
335 depends on HAVE_SHARED && (LDSO_CACHE_SUPPORT || LDSO_PRELOAD_FILE_SUPPORT)
338 If you wish to support both uClibc and glibc on the same system, it
339 is necessary to set this to something other than "ld.so" to avoid
340 conflicts with glibc, which also uses "ld.so". This prevents both
341 libraries from using the same /etc/ld.so.* files. If you wish to
342 support both uClibc and glibc on the same system then you should set
343 this to "ld-uClibc.so".
345 Most people will leave this set to the default of "ld.so".
347 WARNING: Changing the default prefix could cause problems with
350 config LDSO_STANDALONE_SUPPORT
351 bool "Dynamic linker stand-alone mode support"
352 depends on HAVE_SHARED
354 The dynamic linker can be run either indirectly through running some
355 dynamically linked program or library (in which case no command line
356 options to the dynamic linker can be passed and, in the ELF case, the
357 dynamic linker which is stored in the .interp section of the program
358 is executed) or directly by running:
360 /lib/ld-uClibc.so.* [OPTIONS] [PROGRAM [ARGUMENTS]]
362 Stand-alone execution is a prerequisite for adding prelink
363 capabilities to uClibc dynamic linker, as well useful for testing an
364 updated version of the dynamic linker without breaking the system.
366 config LDSO_PRELINK_SUPPORT
367 bool "Dynamic linker prelink support"
368 depends on HAVE_SHARED
369 select LDSO_STANDALONE_SUPPORT
371 The dynamic linker can be used in stand-alone mode by the prelink tool
372 for prelinking ELF shared libraries and binaries to speed up startup
373 time. It also is able to load and handle prelinked libraries and
376 config UCLIBC_STATIC_LDCONFIG
377 bool "Link ldconfig statically"
378 depends on HAVE_SHARED
381 Enable this option to statically link the ldconfig binary.
383 Making ldconfig static can be beneficial if you have a library
384 problem and need to use ldconfig to recover. Sometimes it is
385 preferable to instead keep the size of the system down, in which
386 case you should disable this option.
389 bool "Enable ELF RUNPATH tag support"
390 depends on HAVE_SHARED
391 default y if LDSO_CACHE_SUPPORT
393 ELF's may have dynamic RPATH/RUNPATH tags. These tags list paths
394 which extend the library search paths. They are really only useful
395 if a package installs libraries in non standard locations and
396 ld.so.conf support is disabled.
398 Usage of RUNPATH tags is not too common, so disabling this feature
399 should be safe for most people.
401 config LDSO_RUNPATH_OF_EXECUTABLE
402 bool "Use executables RUNPATH/RPATH when searching for libraries."
403 depends on LDSO_RUNPATH
406 Use the executables RUNPATH/RPATH to find to find libraries even
407 though this behavour is not standard. Setting this option causes
408 the uclibc dynamic linker behavour to match the glibc dynamic linker.
410 config LDSO_SAFE_RUNPATH
411 bool "Allow only RUNPATH beginning with /"
412 depends on LDSO_RUNPATH
415 Allow only absolute path in RPATH/RUNPATH.
417 config LDSO_SEARCH_INTERP_PATH
418 bool "Add ldso path to lib search path"
419 depends on HAVE_SHARED
422 The ldso is told where it is being executed from and can use that
423 path to find related core libraries. This is useful by default,
424 but can be annoying in a mixed development environment.
426 i.e. if the ldso is run from /foo/boo/ldso.so, it will start its
427 library search with /foo/boo/
429 If unsure, simply say Y here.
431 config LDSO_LD_LIBRARY_PATH
432 bool "Add LD_LIBRARY_PATH to lib search path"
433 depends on HAVE_SHARED
436 On hardened system it could be useful to disable the use of
437 LD_LIBRARY_PATH environment variable (a colon-separated list of
438 directories in which to search for ELF libraries at execution-time).
440 If unsure, simply say Y here.
442 config LDSO_NO_CLEANUP
443 bool "Disable automatic unloading of dynamically loaded shared objects"
444 depends on HAVE_SHARED
446 If you need complete allocation traces when debugging memory leaks
447 using Valgrind in a process that dynamically loads shared objects,
448 then answer Y here. Unlike glibc, uClibc unloads all dynamically
449 loaded shared objects when a process exits, which prevents Valgrind
450 from correctly resolving the symbols from the unloaded shared objects.
451 Unless you know you need this, you should answer N.
453 config UCLIBC_CTOR_DTOR
457 If you wish to build uClibc with support for global constructor
458 (ctor) and global destructor (dtor) support, then answer Y here.
459 When ctor/dtor support is enabled, binaries linked with uClibc must
460 also be linked with crtbegin.o and crtend.o which are provided by gcc
461 (the "*startfile:" and "*endfile:" settings in your gcc specs file
462 may need to be adjusted to include these files). This support will
463 also add a small amount of additional size to each binary compiled vs
464 uClibc. If you will be using uClibc with C++, or if you need the gcc
465 __attribute__((constructor)) and __attribute__((destructor)) to work,
466 then you definitely want to answer Y here. If you don't need ctors
467 or dtors and want your binaries to be as small as possible, then
470 config LDSO_GNU_HASH_SUPPORT
471 bool "Enable GNU hash style support"
472 depends on HAVE_SHARED
474 Newest binutils support a new hash style named GNU-hash. The dynamic
475 linker will use the new GNU-hash section (.gnu.hash) for symbol lookup
476 if present into the ELF binaries, otherwise it will use the old SysV
477 hash style (.hash). This ensures that it is completely backward
479 Further, being the hash table implementation self-contained into each
480 executable and shared libraries, objects with mixed hash style can
481 peacefully coexist in the same process.
483 If you want to use this new feature, answer Y
486 prompt "Thread support"
487 default HAS_NO_THREADS
489 If you want to compile uClibc with pthread support, then answer Y.
490 This will increase the size of uClibc by adding a bunch of locking
491 to critical data structures, and adding extra code to ensure that
492 functions are properly reentrant.
494 config HAS_NO_THREADS
497 Disable thread support.
499 config UCLIBC_HAS_LINUXTHREADS
501 # linuxthreads need nanosleep()
502 select UCLIBC_HAS_REALTIME
503 depends on !TARGET_metag
505 If you want to compile uClibc with Linuxthreads support, then answer Y.
507 config UCLIBC_HAS_THREADS_NATIVE
508 bool "Native POSIX Threading (NPTL)"
509 select UCLIBC_HAS_TLS
510 select UCLIBC_HAS_STDIO_FUTEXES
511 select UCLIBC_HAS_REALTIME
512 # i386 has no lowlevellock support (yet) as opposed to i486 onward
513 depends on !CONFIG_386 && \
528 If you want to compile uClibc with NPTL support, then answer Y.
532 config UCLIBC_HAS_THREADS
533 def_bool y if !HAS_NO_THREADS
535 config UCLIBC_HAS_TLS
536 bool "Thread-Local Storage"
537 depends on UCLIBC_HAS_THREADS_NATIVE
539 If you want to enable TLS support then answer Y.
540 This is fast an efficient way to store per-thread local data
541 which is not on stack. It needs __thread support enabled in
544 config PTHREADS_DEBUG_SUPPORT
545 bool "Build pthreads debugging support"
546 depends on UCLIBC_HAS_THREADS
548 Say Y here if you wish to be able to debug applications that use
549 uClibc's pthreads library. By enabling this option, a library
550 named libthread_db will be built. This library will be dlopen()'d
551 by gdb and will allow gdb to debug the threads in your application.
553 IMPORTANT NOTE! Because gdb must dlopen() the libthread_db library,
554 you must compile gdb with uClibc in order for pthread debugging to
557 If you are doing development and want to debug applications using
558 uClibc's pthread library, answer Y. Otherwise, answer N.
561 config UCLIBC_HAS_SYSLOG
562 bool "Syslog support"
564 depends on UCLIBC_HAS_NETWORK_SUPPORT
565 select UCLIBC_HAS_SOCKET
567 Support sending messages to the system logger.
568 This requires socket-support.
571 prompt "Malloc Implementation"
572 default MALLOC if ! ARCH_USE_MMU
573 default MALLOC_STANDARD if ARCH_USE_MMU
578 "malloc" use mmap for all allocations and so works very well on
579 MMU-less systems that do not support the brk() system call. It is
580 pretty smart about reusing already allocated memory, and minimizing
582 This is the default for uClinux MMU-less systems.
587 "malloc-simple" is trivially simple and slow as molasses. It
588 was written from scratch for uClibc, and is the simplest possible
589 (and therefore smallest) malloc implementation.
591 This uses only the mmap() system call to allocate and free memory,
592 and does not use the brk() system call at all, making it a fine
593 choice for MMU-less systems with very limited memory. It's 100%
594 standards compliant, thread safe, very small, and releases freed
595 memory back to the OS immediately rather than keeping it in the
596 process's heap for reallocation. It is also VERY SLOW.
598 config MALLOC_STANDARD
599 bool "malloc-standard"
600 depends on ARCH_USE_MMU
602 "malloc-standard" is derived from the public domain dlmalloc
603 implementation by Doug Lea. It is quite fast, and is pretty smart
604 about reusing already allocated memory, and minimizing memory
605 wastage. This uses brk() for small allocations, while using mmap()
606 for larger allocations. This is the default malloc implementation
609 If unsure, answer "malloc-standard".
613 config MALLOC_GLIBC_COMPAT
614 bool "Malloc returns live pointer for malloc(0)"
616 The behavior of malloc(0) is listed as implementation-defined by
617 SuSv3. Glibc returns a valid pointer to something, while uClibc
618 normally returns NULL. I personally feel glibc's behavior is
619 not particularly safe, and allows buggy applications to hide very
622 When this option is enabled, uClibc will act just like glibc, and
623 return a live pointer when someone calls malloc(0). This pointer
624 provides a malloc'ed area with a size of 1 byte. This feature is
625 mostly useful when dealing with applications using autoconf's broken
626 AC_FUNC_MALLOC macro (which redefines malloc as rpl_malloc if it
627 does not detect glibc style returning-a-valid-pointer-for-malloc(0)
628 behavior). Most people can safely answer N.
630 config UCLIBC_HAS_OBSTACK
631 bool "Obstack Support (gnu extension)"
633 When this option is enabled, uClibc will provide support for obstacks.
634 An obstack is a structure in which memory can be dynamically allocated
635 as a 'stack of objects'. Many programs need this GNU extention and
636 you should say Y if you are using any. Otherwise, say N to save some
639 config UCLIBC_DYNAMIC_ATEXIT
640 bool "Dynamic atexit() Support"
643 When this option is enabled, uClibc will support an infinite number,
644 of atexit() and on_exit() functions, limited only by your available
645 memory. This can be important when uClibc is used with C++, since
646 global destructors are implemented via atexit(), and it is quite
647 possible to exceed the default number when this option is disabled.
648 Enabling this option adds a few bytes, and more significantly makes
649 atexit and on_exit depend on malloc, which can be bad when compiling
652 Unless you use uClibc with C++, you should probably answer N.
655 bool "Old (visible) atexit Support"
657 Enable this option if you want to update from 0.9.28 to git/0.9.29,
658 else you will be missing atexit() until you rebuild all apps.
660 config UCLIBC_HAS_UTMPX
661 bool "utmpx based support for tracking login/logouts to/from the system"
663 Answer y to enable support for accessing user accounting database.
664 It can be used to track all login/logout to the system.
666 config UCLIBC_HAS_UTMP
667 bool "utmp support (XPG2 compat, SVr4 compat)"
668 depends on UCLIBC_HAS_UTMPX
670 Answer y to enable legacy SVID support for accessing
671 user accounting database:
672 getutent(), getutid(), getutline(), pututline(),
673 setutent(), endutent(), utmpname() in utmp.h
674 It can be used to track all login/logout to the system.
676 If unsure, answer N and use corresponding POSIX functions
679 config UCLIBC_SUSV2_LEGACY
680 bool "Enable SuSv2 LEGACY functions"
682 Enable this option if you want to have SuSv2 LEGACY functions
683 Currently applies to:
687 WARNING! ABI incompatibility.
689 config UCLIBC_SUSV3_LEGACY
690 bool "Enable SuSv3 LEGACY functions"
696 Enable this option if you want to have SuSv3 LEGACY functions
697 in the library, else they are replaced by SuSv3 proposed macros.
698 Currently applies to:
700 bcmp, bcopy, bzero, index, rindex, ftime,
701 bsd_signal, (ecvt), (fcvt), gcvt, (getcontext),
702 (getwd), (makecontext),
703 mktemp, (pthread_attr_getstackaddr), (pthread_attr_setstackaddr),
704 scalb, (setcontext), (swapcontext), ualarm, usleep,
707 WARNING! ABI incompatibility.
709 config UCLIBC_HAS_CONTEXT_FUNCS
710 bool "Use obsolescent context control functions"
711 depends on UCLIBC_SUSV3_LEGACY && ARCH_HAS_UCONTEXT
713 Add into library the SuSv3 obsolescent functions used for context
714 control. The setcontext family allows the implementation in C of
715 advanced control flow patterns such as iterators, fibers, and
716 coroutines. They may be viewed as an advanced version of
717 setjmp/longjmp; whereas the latter allows only a single non-local jump
718 up the stack, setcontext allows the creation of multiple cooperative
719 threads of control, each with its own stack.
720 These functions are: setcontext, getcontext, makecontext, swapcontext.
722 config UCLIBC_SUSV3_LEGACY_MACROS
723 bool "Enable SuSv3 LEGACY macros"
725 Enable this option if you want to have SuSv3 LEGACY macros.
726 Currently applies to bcopy/bzero/bcmp/index/rindex et al.
727 WARNING! ABI incompatibility.
729 config UCLIBC_SUSV4_LEGACY
730 bool "Enable SuSv4 LEGACY or obsolescent functions"
732 Enable this option if you want to have SuSv4 LEGACY functions
733 and macros in the library.
734 Currently applies to:
737 _longjmp, _setjmp, _tolower, _toupper, ftw, getitimer,
738 gettimeofday, isascii, pthread_getconcurrency,
739 pthread_setconcurrency, setitimer, setpgrp, sighold,
740 sigignore, sigpause, sigrelse, sigset, siginterrupt,
741 tempnam, toascii, ulimit.
744 asctime, asctime_r, ctime, ctime_r, gets, rand_r,
747 WARNING! ABI incompatibility.
749 config UCLIBC_STRICT_HEADERS
750 bool "Hide structures and constants for unsupported features"
752 Hide structures and constants in headers that should not be used,
753 because the respective feature is disabled.
755 WARNING! enabling this option requires to patch many faulty apps,
756 since they make (wrongly) use of these structures/constants,
757 although the feature was disabled.
759 config UCLIBC_HAS_STUBS
760 bool "Provide stubs for unavailable functionality"
762 With this option uClibc provides non-functional stubs for
763 functions which are impossible to implement on the target
764 architecture. Otherwise, such functions are simply omitted.
766 config UCLIBC_HAS_SHADOW
767 bool "Shadow Password Support"
770 Answer N if you do not need shadow password support.
771 Most people will answer Y.
773 config UCLIBC_HAS_PROGRAM_INVOCATION_NAME
774 bool "Support for program_invocation_name"
776 Support for the GNU-specific program_invocation_name and
777 program_invocation_short_name strings. Some GNU packages
778 (like tar and coreutils) utilize these for extra useful
779 output, but in general are not required.
781 At startup, these external strings are automatically set
782 up based on the value of ARGV[0].
784 If unsure, just answer N.
786 config UCLIBC_HAS___PROGNAME
787 bool "Support for __progname"
790 Some packages (like openssh) like to peek into internal libc
791 symbols to make their output a bit more user friendly.
793 At startup, __progname is automatically set up based on the
796 If unsure, just answer N.
798 config UCLIBC_HAS_PTY
799 bool "Support for pseudo-terminals"
802 This enables support for pseudo-terminals (see man 4 pts
805 If unsure, just answer Y.
808 bool "Assume that /dev/pts is a devpts or devfs file system"
810 depends on UCLIBC_HAS_PTY
812 Enable this if /dev/pts is on a devpts or devfs filesystem. Both
813 these filesystems automatically manage permissions on the /dev/pts
814 devices. You may need to mount your devpts or devfs filesystem on
815 /dev/pts for this to work.
817 Most people should answer Y.
819 config UNIX98PTY_ONLY
820 bool "Support only Unix 98 PTYs"
822 depends on UCLIBC_HAS_PTY
824 If you want to support only Unix 98 PTYs enable this. Some older
825 applications may need this disabled and will thus use legacy BSD
826 style PTY handling which is more complex and also bigger than
827 Unix 98 PTY handling.
829 For most current programs, you can generally answer Y.
832 config UCLIBC_HAS_GETPT
833 bool "Support getpt() (glibc-compat)"
834 depends on UCLIBC_HAS_PTY
836 Some packages may need getpt().
837 All of those are non-standard and can be considered
838 GNU/libc compatibility.
839 Either use posix_openpt() or just open /dev/ptmx yourself.
841 If unsure, just say N.
845 # Have to use __libc_ptyname{1,2}[] and related bloat
846 config UCLIBC_HAS_GETPT
850 config UCLIBC_HAS_LIBUTIL
851 bool "Provide libutil library and functions"
852 depends on UCLIBC_HAS_PTY
854 Provide a libutil library.
855 This non-standard conforming library provides the following
858 forkpty(): combines openpty(), fork(2), and login_tty() to
859 create a new process operating in a pseudo-terminal.
860 login(): write utmp and wtmp entries
861 login_tty(): prepares for a login on the tty fd by creating a
862 new session, making fd the controlling terminal for
863 the calling process, setting fd to be the standard
864 input, output, and error streams of the current
865 process, and closing fd.
866 logout(): write utmp and wtmp entries
867 logwtmp(): constructs a utmp structure and calls updwtmp() to
868 append the structure to the utmp file.
869 openpty(): finds an available pseudo-terminal and returns
870 file descriptors for the master and slave
872 This library adds about 3k-4k to your system.
874 config UCLIBC_HAS_TM_EXTENSIONS
875 bool "Support 'struct tm' timezone extension fields"
878 Enabling this option adds fields to 'struct tm' in time.h for
879 tracking the number of seconds east of UTC, and an abbreviation for
880 the current timezone. These fields are not specified by the SuSv3
881 standard, but they are commonly used in both GNU and BSD application
884 To strictly follow the SuSv3 standard, leave this disabled.
885 Most people will probably want to answer Y.
887 config UCLIBC_HAS_TZ_CACHING
888 bool "Enable caching of the last valid timezone 'TZ' string"
891 Answer Y to enable caching of the last valid 'TZ' string describing
892 the timezone setting. This allows a quick string compare to avoid
893 repeated parsing of unchanged 'TZ' strings when tzset() is called.
895 Most people will answer Y.
897 config UCLIBC_HAS_TZ_FILE
898 bool "Enable '/etc/TZ' file support to set a default timezone (uClibc-specific)"
901 Answer Y to enable the setting of a default timezone for uClibc.
903 Ordinarily, uClibc gets the timezone information exclusively from the
904 'TZ' environment variable. In particular, there is no support for
905 the zoneinfo directory tree or the /etc/timezone file used by glibc.
907 With this option enabled, uClibc will use the value stored in the
908 file '/etc/TZ' (default path) to obtain timezone information if the
909 'TZ' environment variable is missing or has an invalid value. The
910 file consists of a single line (newline required) of text describing
911 the timezone in the format specified for the TZ environment variable.
913 Doing 'echo CST6CDT > /etc/TZ' is enough to create a valid file.
915 http://www.opengroup.org/onlinepubs/007904975/basedefs/xbd_chap08.html
916 for details on valid settings of 'TZ'.
918 Most people will answer Y.
920 config UCLIBC_HAS_TZ_FILE_READ_MANY
921 bool "Repeatedly read the '/etc/TZ' file"
922 depends on UCLIBC_HAS_TZ_FILE
925 Answer Y to enable repeated reading of the '/etc/TZ' file even after
926 a valid value has been read. This incurs the overhead of an
927 open/read/close for each tzset() call (explicit or implied). However,
928 setting this will allow applications to update their timezone
929 information if the contents of the file change.
931 Most people will answer Y.
933 config UCLIBC_TZ_FILE_PATH
934 string "Path to the 'TZ' file for setting the global timezone"
935 depends on UCLIBC_HAS_TZ_FILE
938 This is the path to the 'TZ' file.
940 Most people will use the default of '/etc/TZ'.
942 config UCLIBC_FALLBACK_TO_ETC_LOCALTIME
943 bool "Use /etc/localtime as a fallback"
944 depends on UCLIBC_HAS_TZ_FILE
947 Answer Y to try to use /etc/localtime file.
948 On glibc systems this file (if it is in TZif2 format)
949 contains timezone string at the end.
951 Most people will answer Y.
955 menu "Advanced Library Settings"
957 config UCLIBC_PWD_BUFFER_SIZE
958 int "Buffer size for getpwnam() and friends"
962 This sets the value of the buffer size for getpwnam() and friends.
963 By default, this is 256. (For reference, glibc uses 1024).
964 The value can be found using sysconf() with the _SC_GETPW_R_SIZE_MAX
967 config UCLIBC_GRP_BUFFER_SIZE
968 int "Buffer size for getgrnam() and friends"
972 This sets the value of the buffer size for getgrnam() and friends.
973 By default, this is 256. (For reference, glibc uses 1024).
974 The value can be found using sysconf() with the _SC_GETGR_R_SIZE_MAX
977 comment "Support various families of functions"
979 config UCLIBC_LINUX_MODULE_26
980 bool "Linux kernel module functions (2.6)"
983 delete_module, init_module
984 are used in linux for loadable kernel modules.
986 Say N if you do not use kernel modules.
988 config UCLIBC_LINUX_SPECIFIC
989 bool "Linux specific functions"
992 accept4(), bdflush(),
993 capget(), capset(), eventfd(), fallocate(),
994 fstatfs(), getrandom(), inotify_*(), ioperm(), iopl(),
995 madvise(), modify_ldt(), pipe2(), personality(),
996 prctl()/arch_prctl(), pivot_root(), modify_ldt(),
997 ppoll(), readahead(), reboot(), remap_file_pages(),
998 sched_getaffinity(), sched_setaffinity(), sendfile(),
999 setfsgid(), setfsuid(), setresgid(), setresuid(),
1000 splice(), vmsplice(), tee(), signalfd(), statfs(),
1001 swapoff(), swapon(), sync_file_range(), syncfs(),
1002 _sysctl(), sysinfo(), timerfd_*(), vhangup(), umount(),
1005 config UCLIBC_HAS_GNU_ERROR
1006 bool "Support GNU extensions for error-reporting"
1009 Support for the GNU-specific error(), error_at_line(),
1010 void (* error_print_progname)(), error_message_count
1011 functions and variables. Some GNU packages
1012 utilize these for extra useful output, but in general
1015 If unsure, just answer N.
1017 config UCLIBC_BSD_SPECIFIC
1018 bool "BSD specific functions"
1021 mincore(), getdomainname(), setdomainname()
1025 config UCLIBC_HAS_BSD_ERR
1026 bool "BSD err functions"
1029 These functions are non-standard BSD extensions.
1030 err(), errx(), warn(), warnx(), verr(), verrx(), vwarn(), vwarnx()
1034 config UCLIBC_HAS_OBSOLETE_BSD_SIGNAL
1035 bool "BSD obsolete signal functions"
1037 These functions are provided as a compatibility interface for
1038 programs that make use of the historical System V signal API.
1039 This API is obsolete:
1040 new applications should use the POSIX signal API (sigaction(2),
1041 sigprocmask(2), etc.).
1044 sigset(), sighold(), sigrelse(), sigignore()
1048 config UCLIBC_HAS_OBSOLETE_SYSV_SIGNAL
1049 bool "SYSV obsolete signal functions"
1051 Use of sysv_signal() should be avoided; use sigaction(2) instead.
1055 config UCLIBC_NTP_LEGACY
1056 bool "ntp_*() aliases"
1058 Provide legacy aliases for ntp functions:
1059 ntp_adjtime(), ntp_gettime()
1061 It is safe to say N here.
1063 config UCLIBC_SV4_DEPRECATED
1064 bool "Enable SVr4 deprecated functions"
1066 These functions are DEPRECATED in System V release 4.
1067 Say N unless you desparately need one of the functions below:
1069 ustat() [use statfs(2) in your code instead]
1071 config UCLIBC_HAS_REALTIME
1072 bool "Realtime-related family of SUSv functions"
1075 These functions are part of the Timers option and need not
1076 be available on all implementations.
1077 Includes AIO, message-queue, scheduler, semaphore functions:
1092 clock_getres(), clock_gettime(), clock_settime()
1094 mlockall(), munlockall()
1106 sched_get_priority_max(), sched_get_priority_min()
1107 sched_getscheduler()
1108 sched_rr_get_interval()
1110 sched_setscheduler()
1117 sem_trywait(), sem_wait()
1120 sigtimedwait(), sigwaitinfo()
1123 timer_getoverrun(), timer_gettime(), timer_settime()
1125 config UCLIBC_HAS_ADVANCED_REALTIME
1126 bool "Advanced realtime-related family of SUSv functions"
1128 depends on UCLIBC_HAS_REALTIME
1130 These functions are part of the Timers option and need not
1131 be available on all implementations.
1133 clock_getcpuclockid()
1142 posix_spawnattr_destroy(), posix_spawnattr_init()
1143 posix_spawnattr_getflags(), posix_spawnattr_setflags()
1144 posix_spawnattr_getpgroup(), posix_spawnattr_setpgroup()
1145 posix_spawnattr_getschedparam(), posix_spawnattr_setschedparam()
1146 posix_spawnattr_getschedpolicy(), posix_spawnattr_setschedpolicy()
1147 posix_spawnattr_getsigdefault(), posix_spawnattr_setsigdefault()
1148 posix_spawnattr_getsigmask(), posix_spawnattr_setsigmask()
1149 posix_spawn_file_actions_addclose()
1150 posix_spawn_file_actions_adddup2()
1151 posix_spawn_file_actions_addopen()
1152 posix_spawn_file_actions_destroy()
1153 posix_spawn_file_actions_init()
1156 posix_typed_mem_get_info()
1157 pthread_mutex_timedlock()
1160 #config UCLIBC_HAS_TERMIOS
1161 # bool "termios functions"
1164 # Get and set terminal attributes, line control, get and set baud
1166 # termios(), tcgetattr(), tcsetattr(), tcsendbreak(), tcdrain(),
1167 # tcflush(), tcflow(), cfmakeraw(), cfgetospeed(), cfgetispeed(),
1168 # cfsetispeed(), cfsetospeed(), cfsetspeed()
1172 config UCLIBC_HAS_EPOLL
1176 epoll_create(), epoll_ctl(), epoll_wait() functions.
1178 config UCLIBC_HAS_XATTR
1179 bool "Extended Attributes"
1182 Extended Attributes support.
1197 Say N unless you need support for extended attributes and the
1198 filesystems do actually support them.
1200 config UCLIBC_HAS_PROFILING
1201 bool "Profiling support"
1204 gcc's -finstrument-functions needs these.
1206 Most people can safely answer N.
1208 config UCLIBC_HAS_CRYPT_IMPL
1209 bool "libcrypt support"
1212 libcrypt contains crypt(), setkey() and encrypt()
1214 config UCLIBC_HAS_SHA256_CRYPT_IMPL
1215 bool "libcrypt SHA256 support"
1216 depends on UCLIBC_HAS_CRYPT_IMPL
1218 This adds support for SHA256 password hashing via the crypt() function.
1219 Say N here if you do not need SHA256 crypt support.
1221 config UCLIBC_HAS_SHA512_CRYPT_IMPL
1222 bool "libcrypt SHA512 support"
1223 depends on UCLIBC_HAS_CRYPT_IMPL
1225 This adds support for SHA512 password hashing via the crypt() function.
1226 Say N here if you do not need SHA512 crypt support.
1228 config UCLIBC_HAS_CRYPT_STUB
1229 bool "libcrypt stubs"
1231 depends on !UCLIBC_HAS_CRYPT_IMPL
1233 Standards mandate that crypt(3) provides a stub if it is unavailable.
1234 If you enable this option then stubs for
1235 crypt(), setkey() and encrypt()
1236 will be provided in a small libcrypt.
1238 config UCLIBC_HAS_CRYPT
1240 depends on UCLIBC_HAS_CRYPT_IMPL || UCLIBC_HAS_CRYPT_STUB
1243 menuconfig UCLIBC_HAS_NETWORK_SUPPORT
1244 bool "Networking Support"
1247 Say N here if you do not need network support.
1249 if UCLIBC_HAS_NETWORK_SUPPORT
1250 config UCLIBC_HAS_SOCKET
1251 bool "Socket support"
1254 If you want to include support for sockets then answer Y.
1256 config UCLIBC_HAS_IPV4
1257 bool "IP version 4 support"
1259 select UCLIBC_HAS_SOCKET
1261 If you want to include support for the Internet Protocol
1262 (IP version 4) then answer Y.
1264 Most people will say Y.
1266 config UCLIBC_HAS_IPV6
1267 bool "IP version 6 support"
1268 select UCLIBC_HAS_SOCKET
1270 If you want to include support for the next version of the Internet
1271 Protocol (IP version 6) then answer Y.
1273 Most people should answer N.
1275 config UCLIBC_HAS_RPC
1276 bool "Remote Procedure Call (RPC) support"
1277 # RPC+socket-ipvX doesn't currently work.
1278 depends on UCLIBC_HAS_IPV4 || UCLIBC_HAS_IPV6
1280 If you want to include RPC support, enable this. RPC is rarely used
1281 for anything except for the NFS filesystem. Unless you plan to use
1282 NFS, you can probably leave this set to N and save some space.
1284 If you need to use NFS then you should answer Y.
1286 config UCLIBC_HAS_FULL_RPC
1287 bool "Full RPC support"
1288 depends on UCLIBC_HAS_RPC
1289 default y if !HAVE_SHARED
1291 Normally we enable just enough RPC support for things like rshd and
1292 nfs mounts to work. If you find you need the rest of the RPC stuff,
1293 then enable this option. Most people can safely answer N.
1295 config UCLIBC_HAS_REENTRANT_RPC
1296 bool "Reentrant RPC support"
1297 depends on UCLIBC_HAS_RPC
1298 default y if !HAVE_SHARED
1300 Most packages utilize the normal (non-reentrant) RPC functions, but
1301 some (like exportfs from nfs-utils) need these reentrant versions.
1303 Most people can safely answer N.
1305 config UCLIBC_USE_NETLINK
1306 bool "Use netlink to query interfaces"
1307 depends on UCLIBC_HAS_SOCKET
1309 In newer versions of Linux (2.4.17+), support was added for querying
1310 network device information via netlink rather than the old style
1311 ioctl's. Most of the time, the older ioctl style is sufficient (and
1312 it is smaller than netlink), but if you find that not all of your
1313 devices are being returned by the if_nameindex() function, you will
1314 have to use the netlink implementation.
1316 Most people can safely answer N.
1318 config UCLIBC_SUPPORT_AI_ADDRCONFIG
1319 bool "Support the AI_ADDRCONFIG flag"
1320 depends on UCLIBC_USE_NETLINK
1322 The implementation of AI_ADDRCONFIG is aligned with the glibc
1323 implementation using netlink to query interfaces to find both
1324 ipv4 and ipv6 support. This is only needed if an application uses
1325 the AI_ADDRCONFIG flag.
1327 Most people can safely answer N.
1329 config UCLIBC_HAS_BSD_RES_CLOSE
1330 bool "Support res_close() (bsd-compat)"
1332 Answer Y if you desperately want to support BSD compatibility in
1335 Most people will say N.
1337 config UCLIBC_HAS_COMPAT_RES_STATE
1338 bool "Use compatible but bloated _res"
1341 Answer Y if you build network utilities and they muck with resolver
1342 internals a lot (_res global structure). uclibc does not use most
1343 of _res.XXX fields, and with this option OFF they won't even exist.
1344 Which will make e.g. dig build fail.
1345 Answering N saves around 400 bytes in bss.
1347 config UCLIBC_HAS_EXTRA_COMPAT_RES_STATE
1348 bool "Use extra compatible but extra bloated _res"
1350 Answer Y if selecting UCLIBC_HAS_COMPAT_RES_STATE is not enough.
1351 As far as I can say, this should never be needed.
1353 config UCLIBC_HAS_RESOLVER_SUPPORT
1354 bool "DNS resolver functions"
1355 select UCLIBC_HAS_COMPAT_RES_STATE
1356 depends on UCLIBC_HAS_IPV4 || UCLIBC_HAS_IPV6
1358 Provide implementations for DNS resolver functions.
1359 In particular, the following functions will be added to the
1362 ns_skiprr, ns_initparse, ns_parserr, ns_msg_getflag,
1363 res_mkquery, res_init, res_ninit, res_close, res_nclose
1364 res_query, res_search, res_querydomain,
1366 ns_name_uncompress, ns_name_ntop, ns_name_pton, ns_name_unpack,
1367 ns_name_pack, ns_name_compress, ns_name_skip, dn_skipname,
1368 ns_get16, ns_get32, ns_put16, ns_put32
1373 menu "String and Stdio Support"
1375 config UCLIBC_HAS_STRING_GENERIC_OPT
1376 bool "Use faster (but larger) generic string functions"
1379 Answer Y to use the (tweaked) glibc generic string functions.
1381 In general, they are faster (but 3-5K larger) than the base
1382 uClibc string functions which are optimized solely for size.
1384 Many people will answer Y.
1386 config UCLIBC_HAS_STRING_ARCH_OPT
1387 bool "Use arch-specific assembly string functions (where available)"
1390 Answer Y to use any archtecture-specific assembly language string
1391 functions available for this target plaform.
1393 Note that assembly implementations are not available for all string
1394 functions, so some generic (written in C) string functions may
1397 These are small and fast, the only reason _not_ to say Y here is
1398 for debugging purposes.
1400 config UCLIBC_HAS_STDIO_FUTEXES
1401 bool "Use futexes for multithreaded I/O locking"
1402 depends on UCLIBC_HAS_THREADS_NATIVE
1404 If you want to compile uClibc to use futexes for low-level
1405 I/O locking, answer Y. Otherwise, answer N.
1407 config UCLIBC_HAS_CTYPE_TABLES
1408 bool "Use Table Versions Of 'ctype.h' Functions."
1411 Answer Y to use table versions of the 'ctype.h' functions.
1412 While the non-table versions are often smaller when building
1413 statically linked apps, they work only in stub locale mode.
1415 Most people will answer Y.
1417 config UCLIBC_HAS_CTYPE_SIGNED
1418 bool "Support Signed Characters In 'ctype.h' Functions."
1419 depends on UCLIBC_HAS_CTYPE_TABLES
1422 Answer Y to enable support for passing signed char values to
1423 the 'ctype.h' functions. ANSI/ISO C99 and SUSv3 specify that
1424 these functions are only defined for unsigned char values and
1425 EOF. However, glibc allows negative signed char values as well
1426 in order to support 'broken old programs'.
1428 Most people will answer Y.
1431 prompt "ctype argument checking"
1432 depends on UCLIBC_HAS_CTYPE_TABLES
1433 default UCLIBC_HAS_CTYPE_UNSAFE
1435 Please select the invalid arg behavior you want for the 'ctype'
1438 The 'ctype' functions are now implemented using table lookups, with
1439 the arg being the index. This can result in incorrect memory accesses
1440 or even segfaults for args outside of the allowed range.
1442 NOTE: This only affects the 'ctype' _functions_. It does not affect
1443 the macro implementations.
1445 config UCLIBC_HAS_CTYPE_UNSAFE
1446 bool "Do not check -- unsafe"
1448 config UCLIBC_HAS_CTYPE_CHECKED
1449 bool "Detect and handle appropriately"
1451 config UCLIBC_HAS_CTYPE_ENFORCED
1452 bool "Issue a diagnostic and abort()"
1457 config UCLIBC_HAS_WCHAR
1458 bool "Wide Character Support"
1460 Answer Y to enable wide character support. This will make uClibc
1461 much larger. It is also currently required for locale support.
1463 Most people will answer N.
1465 config UCLIBC_HAS_LOCALE
1466 bool "Locale Support"
1467 select UCLIBC_HAS_WCHAR
1468 select UCLIBC_HAS_CTYPE_TABLES
1470 uClibc now has full ANSI/ISO C99 locale support (except for
1471 wcsftime() and collating items in regex). Be aware that enabling
1472 this option will make uClibc much larger.
1474 Enabling UCLIBC_HAS_LOCALE with the default set of supported locales
1475 (169 UTF-8 locales, and 144 locales for other codesets) will enlarge
1476 uClibc by around 300k. You can reduce this size by building your own
1477 custom set of locate data (see extra/locale/LOCALES for details).
1479 uClibc's locale support is still under development. For example,
1480 codesets using shift states are not currently supported. Support is
1481 planned in the next iteration of locale support.
1483 Answer Y to enable locale support. Most people will answer N.
1487 prompt "Locale data"
1488 depends on UCLIBC_HAS_LOCALE
1489 default UCLIBC_BUILD_MINIMAL_LOCALE
1491 config UCLIBC_BUILD_MINIMAL_LOCALE
1492 bool "Only selected locales"
1493 depends on UCLIBC_HAS_LOCALE
1495 If you do not need all locales that are available on your
1496 host-box, then set this to 'Y'.
1498 config UCLIBC_BUILD_ALL_LOCALE
1500 depends on UCLIBC_HAS_LOCALE
1502 This builds all the locales that are available on your
1507 config UCLIBC_BUILD_MINIMAL_LOCALES
1508 string "locales to use"
1509 depends on UCLIBC_BUILD_MINIMAL_LOCALE
1512 Space separated list of locales to use.
1519 config UCLIBC_HAS_XLOCALE
1520 bool "Extended Locale Support (experimental/incomplete)"
1521 depends on UCLIBC_HAS_LOCALE
1523 Answer Y to enable extended locale support similar to that provided
1524 by glibc. This is primarily intended to support libstd++
1526 However, it also allows thread-specific locale selection via
1529 Most people will answer N.
1531 config UCLIBC_HAS_HEXADECIMAL_FLOATS
1532 bool "Support hexadecimal float notation"
1533 depends on UCLIBC_HAS_CTYPE_TABLES
1534 depends on UCLIBC_HAS_FLOATS
1536 Answer Y to enable support for hexadecimal float notation in the
1537 (wchar and) char string to floating point conversion functions, as
1538 well as support for the %a and %A conversion specifiers in the
1539 *printf() and *scanf() functions.
1541 Most people will answer N.
1543 config UCLIBC_HAS_GLIBC_DIGIT_GROUPING
1544 bool "Support glibc's \"'\" flag for allowing locale-specific digit grouping"
1545 depends on UCLIBC_HAS_LOCALE
1546 depends on UCLIBC_HAS_FLOATS
1548 Answer Y to enable support for glibc's \"'\" flag for allowing
1549 locale-specific digit grouping in base 10 integer conversions and
1550 appropriate floating point conversions in the *printf() and *scanf()
1553 Most people will answer N.
1555 config UCLIBC_HAS_SCANF_LENIENT_DIGIT_GROUPING
1556 bool "Do not require digit grouping when the \"'\" flag is specified"
1557 depends on UCLIBC_HAS_GLIBC_DIGIT_GROUPING
1560 Answer Y to make digit grouping optional when the \"'\" flag is
1562 This is the standard glibc behavior. If the initial string of digits
1563 exceeds the maximum group number, the input will be treated as a
1564 normal non-grouped number.
1566 Most people will answer N.
1568 config UCLIBC_HAS_GLIBC_CUSTOM_PRINTF
1569 bool "Support glibc's register_printf_function() (glibc-compat)"
1570 depends on !USE_OLD_VFPRINTF
1572 Answer Y to support glibc's register_printf_function() to allow an
1573 application to add its own printf conversion specifiers.
1574 parse_printf_format() is also enabled.
1576 NOTE: Limits the number or registered specifiers to 10.
1577 NOTE: Requires new conversion specifiers to be ASCII
1578 characters (0-0x7f). This is to avoid problems with processing
1579 format strings in locales with different multibyte conversions.
1581 Most people will answer N.
1583 config USE_OLD_VFPRINTF
1584 bool "Use the old vfprintf implementation"
1585 depends on !UCLIBC_HAS_WCHAR
1587 Set to true to use the old vfprintf instead of the new. This is
1588 roughly C89 compliant with some extensions, and is much smaller.
1589 However, it does not support wide chars, positional args, or glibc
1590 custom printf specifiers.
1592 Most people will answer N.
1594 config UCLIBC_PRINTF_SCANF_POSITIONAL_ARGS
1595 int "Maximum number of positional args. Either 0 or >= 9."
1596 depends on !USE_OLD_VFPRINTF
1599 Set the maximum number of positional args supported by the
1600 printf/scanf functions. The Single Unix Specification Version 3
1601 requires a minimum value of 9. Setting this to a value lower than
1602 9 will disable positional arg support and cause the NL_ARGMAX macro
1603 in limits.h to be #undef'd.
1605 WARNING! The workspace to support positional args is currently
1606 allocated on the stack. You probably don't want to set
1607 this to too high a value.
1609 Most people will answer 9.
1612 prompt "Stdio buffer size"
1613 default UCLIBC_HAS_STDIO_BUFSIZ_4096
1615 Please select a value for BUFSIZ. This will be used by the
1616 stdio subsystem as the default buffer size for a file, and
1617 affects fopen(), setvbuf(), etc.
1619 NOTE: Setting this to 'none' will disable buffering completely.
1620 However, BUFSIZ will still be defined in stdio.h as 256 because
1621 many applications use this value.
1623 config UCLIBC_HAS_STDIO_BUFSIZ_NONE
1624 bool "none (WARNING - BUFSIZ will be 256 in stdio.h)"
1625 depends on !UCLIBC_HAS_WCHAR
1627 config UCLIBC_HAS_STDIO_BUFSIZ_256
1628 bool "256 (minimum ANSI/ISO C99 value)"
1630 config UCLIBC_HAS_STDIO_BUFSIZ_512
1633 config UCLIBC_HAS_STDIO_BUFSIZ_1024
1636 config UCLIBC_HAS_STDIO_BUFSIZ_2048
1639 config UCLIBC_HAS_STDIO_BUFSIZ_4096
1642 config UCLIBC_HAS_STDIO_BUFSIZ_8192
1645 # If you add more choices, you will need to update uClibc_stdio.h.
1650 prompt "Stdio builtin buffer size (uClibc-specific)"
1651 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1652 default UCLIBC_HAS_STDIO_BUILTIN_BUFFER_NONE
1654 When a FILE is created with fopen(), an attempt is made to allocate
1655 a BUFSIZ buffer for it. If the allocation fails, fopen() will still
1656 succeed but the FILE will be unbuffered.
1658 This option adds a small amount of space to each FILE to act as an
1659 emergency buffer in the event of a buffer allocation failure.
1661 Most people will answer None.
1663 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_NONE
1666 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_4
1669 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_8
1672 # If you add more choices, you will need to update uClibc_stdio.h.
1676 config UCLIBC_HAS_STDIO_SHUTDOWN_ON_ABORT
1677 bool "Attempt to shutdown stdio subsystem when abort() is called."
1679 ANSI/ISO C99 requires abort() to be asyn-signal-safe. So there was
1680 a behavioral change made in SUSv3. Previously, abort() was required
1681 to have the affect of fclose() on all open streams. The wording has
1682 been changed to "may" from "shall".
1684 Most people will answer N.
1686 config UCLIBC_HAS_STDIO_GETC_MACRO
1687 bool "Provide a macro version of getc()"
1688 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1691 Provide a macro version of getc().
1693 Most people will answer Y.
1695 config UCLIBC_HAS_STDIO_PUTC_MACRO
1696 bool "Provide a macro version of putc()"
1697 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1700 Provide a macro version of putc().
1702 Most people will answer Y.
1704 config UCLIBC_HAS_STDIO_AUTO_RW_TRANSITION
1705 bool "Support auto-r/w transition"
1708 Answer Y to enable the stdio subsystem to automaticly transition
1709 between reading and writing. This relaxes the ANSI/ISO C99
1712 When a file is opened with update mode ('+' as the second or third
1713 character in the list of mode argument values), both input and output
1714 may be performed on the associated stream. However, output shall not
1715 be directly followed by input without an intervening call to the
1716 fflush function or to a file positioning function (fseek, fsetpos,
1717 or rewind), and input shall not be directly followed by output without
1718 an intervening call to a file positioning function, unless the input
1719 operation encounters endÂofÂfile.
1721 Most people will answer Y.
1723 config UCLIBC_HAS_FOPEN_LARGEFILE_MODE
1724 bool "Support an fopen() 'F' flag for large file mode (uClibc-specific)"
1726 Answer Y to enable a uClibc-specific extension to allow passing an
1727 additional 'F' flag in the mode string for fopen() to specify that
1728 the file should be open()ed with the O_LARGEFILE flag set.
1730 Most people will answer N.
1732 config UCLIBC_HAS_FOPEN_EXCLUSIVE_MODE
1733 bool "Support an fopen() 'x' flag for exclusive mode (glibc-compat)"
1735 Answer Y to support a glibc extension to allow passing
1736 additional 'x' flag in the mode string for fopen() to specify that
1737 the file should be open()ed with the O_EXCL flag set.
1739 Most people will answer N.
1741 config UCLIBC_HAS_FOPEN_CLOSEEXEC_MODE
1742 bool "Support an fopen() 'e' flag for close-on-exec mode (glibc-compat)"
1744 Answer Y to support a glibc extension to allow passing
1745 additional 'e' flag in the mode string for fopen() to specify that
1746 the file should be open()ed with the O_CLOEXEC flag set.
1748 Most people will answer N.
1750 config UCLIBC_HAS_GLIBC_CUSTOM_STREAMS
1751 bool "Support fmemopen(), open_memstream(), and fopencookie() (glibc-compat)"
1753 Answer Y to support the glibc 'custom stream' extension functions
1754 fmemopen(), open_memstream(), and fopencookie().
1756 NOTE: There are some minor differences regarding seeking behavior.
1758 Most people will answer N.
1760 config UCLIBC_HAS_PRINTF_M_SPEC
1761 bool "Support the '%m' specifier in printf format strings (glibc-compat)"
1763 Answer Y to support a glibc extension to interpret '%m' in printf
1764 format strings as an instruction to output the error message string
1765 (as generated by strerror) corresponding to the current value of
1768 Most people will answer N.
1770 config UCLIBC_HAS_ERRNO_MESSAGES
1771 bool "Include the errno message text in the library"
1774 Answer Y if you want to include the errno message text in the
1775 library. This adds about 3K to the library, but enables strerror()
1776 to generate text other than 'Unknown error <number>'.
1778 Most people will answer Y.
1780 config UCLIBC_HAS_SYS_ERRLIST
1781 bool "Support sys_errlist[] (obsolete-compat)"
1782 depends on UCLIBC_HAS_ERRNO_MESSAGES
1784 Answer Y if you want to support the obsolete sys_errlist[].
1785 This adds about 0.5k to the library, except for the mips
1786 arch where it adds over 4K.
1788 WARNING! In the future, support for sys_errlist[] may be unavailable
1789 in at least some configurations. In fact, it may be removed
1792 Most people will answer N.
1794 Application writers: use the strerror(3) function.
1796 config UCLIBC_HAS_SIGNUM_MESSAGES
1797 bool "Include the signum message text in the library"
1800 Answer Y if you want to include the signum message text in the
1801 library. This adds about 0.5K to the library, but enables strsignal()
1802 to generate text other than 'Unknown signal <number>'.
1804 Most people will answer Y.
1806 config UCLIBC_HAS_SYS_SIGLIST
1807 bool "Support sys_siglist[] (bsd-compat)"
1808 depends on UCLIBC_HAS_SIGNUM_MESSAGES
1810 Answer Y if you want to support sys_siglist[].
1812 WARNING! In the future, support for sys_siglist[] may be unavailable
1813 in at least some configurations. In fact, it may be removed
1816 Most people will answer N.
1818 config UCLIBC_HAS_GNU_GETOPT
1819 bool "Support gnu getopt"
1822 Answer Y if you want to include full gnu getopt() instead of a
1823 (much smaller) SUSv3 compatible getopt().
1824 Note that getopt_long, getopt_long_only as well as getsubopt
1825 are implemented on top of this choice.
1827 Most people will answer Y.
1829 config UCLIBC_HAS_GETOPT_LONG
1830 bool "Support getopt_long/getopt_long_only (glibc-compat)"
1833 Answer Y if you want to include getopt_long[_only()] used by many
1836 Most people will answer Y.
1838 config UCLIBC_HAS_GNU_GETSUBOPT
1839 bool "Support getsubopt"
1842 Answer Y if you want to include getsubopt().
1844 Most people will answer Y.
1846 config UCLIBC_HAS_ARGP
1847 bool "Support argp (as standalone shared object)"
1848 select UCLIBC_HAS_GETOPT_LONG
1849 select UCLIBC_HAS_GNU_GETOPT
1852 Argp is an interface for parsing unix-style argument vectors. Unlike
1853 the common getopt interface, it provides many advanced features in
1854 addition to parsing options, such as automatic output in response to
1855 `--help' and `--version' options.
1856 A library can export an argp option parser, which programs can easily
1857 use in conjunction with their own option parser.
1858 Argp support is needed by elfutils libdw.
1860 Most people can safely answer N.
1867 config UCLIBC_HAS_REGEX
1868 bool "Regular Expression Support"
1871 POSIX regular expression code is really big -- 53k all by itself.
1872 If you don't use regular expressions, turn this off and save space.
1873 Of course, if you only statically link, leave this on, since it will
1874 only be included in your apps if you use regular expressions.
1876 config UCLIBC_HAS_REGEX_OLD
1877 bool "Use the older (stable) regular expression code"
1878 depends on UCLIBC_HAS_REGEX
1881 There are two versions of regex. The older (stable) version has
1882 been in uClibc for quite a long time but hasn't seen too many
1883 updates. It also has some known issues when dealing with uncommon
1884 corner cases and multibyte/unicode strings. However, it is quite
1885 a bit smaller than the newer version.
1887 If the older version has worked for you and you don't need unicode
1888 support, then stick with the old version (and say Y here).
1889 Otherwise, you should use the new version (and say N here).
1891 config UCLIBC_HAS_FNMATCH
1892 bool "fnmatch Support"
1897 config UCLIBC_HAS_FNMATCH_OLD
1898 bool "Use the older (stable) fnmatch code"
1899 depends on UCLIBC_HAS_FNMATCH
1902 There are two versions of fnmatch. The older (stable) version has
1903 been in uClibc for quite a long time but hasn't seen too many
1904 updates. It also has some known issues when dealing with uncommon
1905 corner cases and multibyte/unicode strings. However, it is quite
1906 a bit smaller than the newer version.
1908 If the older version has worked for you and you don't need unicode
1909 support, then stick with the old version (and say Y here).
1910 Otherwise, you should use the new version (and say N here).
1912 config UCLIBC_HAS_WORDEXP
1913 bool "Support the wordexp() interface"
1914 depends on UCLIBC_HAS_GLOB
1916 The SuSv3 wordexp() interface performs word expansions per the Shell
1917 and Utilities volume of IEEE Std 1003.1-2001, Section 2.6. It is
1918 intended for use by applications that want to implement all of the
1919 standard Bourne shell expansions on input data.
1921 This interface is rarely used, and very large. Unless you have a
1922 pressing need for wordexp(), you should probably answer N.
1924 config UCLIBC_HAS_NFTW
1925 bool "Support the nftw() interface"
1927 The SuSv3 nftw() interface is used to recursively descend
1928 directory paths while repeatedly calling a function.
1930 This interface is rarely used, and adds around 4.5k. Unless you have
1931 a pressing need for nftw(), you should probably answer N.
1933 config UCLIBC_HAS_FTW
1934 bool "Support the ftw() interface (SUSv4-obsolete)"
1935 depends on UCLIBC_SUSV4_LEGACY
1937 The SuSv3 ftw() interface is used to recursively descend
1938 directory paths while repeatedly calling a function.
1940 This interface is rarely used, and adds around 4.5k. Unless you have
1941 a pressing need for ftw(), you should probably answer N.
1943 config UCLIBC_HAS_FTS
1944 bool "Support the fts() interface (bsd-compat)"
1946 The fts functions are provided for traversing UNIX file hierarchies.
1948 This interface is currently used by the elfutils and adds
1950 You should port your application to use the POSIX nftw()
1953 Unless you need to build/use elfutils, you should prolly answer N.
1955 config UCLIBC_HAS_GLOB
1956 bool "Support the glob() interface"
1957 depends on UCLIBC_HAS_FNMATCH
1961 The glob interface is somewhat large (weighing in at about 2,5k). It
1962 is used fairly often, but is an option since people wanting to go for
1963 absolute minimum size may wish to omit it.
1965 Most people will answer Y.
1967 config UCLIBC_HAS_GNU_GLOB
1968 bool "Support gnu glob() interface"
1969 depends on UCLIBC_HAS_GLOB
1971 The gnu glob interface is somewhat larger (weighing in at about 4,2k)
1972 than it's SuSv3 counterpart (and is out of date). It is an old copy
1973 from glibc and does not support all the GNU specific options.
1975 Answer Y if you want to include full gnu glob() instead of the smaller
1976 SUSv3 compatible glob().
1978 Most people will answer N.
1985 menu "Library Installation Options"
1987 config RUNTIME_PREFIX
1988 string "uClibc runtime library directory"
1989 default "/usr/$(TARGET_ARCH)-linux-uclibc/"
1991 RUNTIME_PREFIX is the directory into which the uClibc runtime
1992 libraries will be installed. The result will look something
1995 lib/ <contains all runtime libraries>
1996 usr/bin/ldd <the ldd utility program>
1997 sbin/ldconfig <the ldconfig utility program>
1998 This value is used by the 'make install' Makefile target. Since this
1999 directory is compiled into the shared library loader, you will need to
2000 recompile uClibc if you change this value...
2002 For a typical target system this should be set to "/", such that
2003 'make install' will install /lib/libuClibc-<VERSION>.so
2006 string "uClibc development environment directory"
2007 default "/usr/$(TARGET_ARCH)-linux-uclibc/usr/"
2009 DEVEL_PREFIX is the directory into which the uClibc development
2010 environment will be installed. The result will look something
2013 lib/ <contains static libs>
2014 include/ <Where all the header files go>
2015 This value is used by the 'make install' Makefile target when
2016 installing a uClibc development environment.
2018 For a typical target system this should be set to "/usr", such that
2019 'make install' will install /usr/include/<header files>.
2022 string "library path component"
2025 Path component where libraries reside.
2027 For a typical target system this should be set to "lib", such that
2028 'make install' will install libraries to "/lib" and "/usr/lib"
2030 DEVEL_PREFIX/MULTILIB_DIR
2031 RUNTIME_PREFIX/MULTILIB_DIR
2033 Other settings may include "lib32" or "lib64".
2035 config HARDWIRED_ABSPATH
2036 bool "Hardwire absolute paths into linker scripts"
2039 This prepends absolute paths to the libraries mentioned in linker
2040 scripts such as libc.so.
2042 This is a build time optimization. It has no impact on dynamic
2043 linking at runtime, which doesn't use linker scripts.
2045 You must disable this to use uClibc with old non-sysroot toolchains,
2046 such as the prebuilt binary cross compilers at:
2047 http://uclibc.org/downloads/binaries
2049 The amount of time saved by this optimization is actually too small to
2050 measure. The linker just had to search the library path to find the
2051 linker script, so the dentries are cache hot if it has to search the
2052 same path again. But it's what glibc does, so we do it too.
2057 menu "Security options"
2059 config UCLIBC_BUILD_PIE
2060 bool "Build utilities as ET_DYN/PIE executables"
2061 depends on HAVE_SHARED
2062 depends on TARGET_arm || TARGET_frv || TARGET_i386 || TARGET_mips || TARGET_powerpc || TARGET_nds32
2063 select FORCE_SHAREABLE_TEXT_SEGMENTS
2065 If you answer Y here, ldd and iconv are built as ET_DYN/PIE
2068 It requires gcc-3.4 and binutils-2.15 (for arm 2.16) or later.
2069 More about ET_DYN/PIE binaries on <http://pax.grsecurity.net/> .
2071 WARNING: This option also enables FORCE_SHAREABLE_TEXT_SEGMENTS, so
2072 all libraries have to be built with -fPIC or -fpic, and all
2073 assembler functions must be written as position independent
2076 config UCLIBC_HAS_ARC4RANDOM
2077 bool "Include the arc4random() function"
2079 Answer Y to support the OpenBSD-like arc4random() function. This
2080 function picks a random number between 0 and N, and will always return
2081 something even if the random driver is dead. If urandom fails then
2082 gettimeofday(2) will be used as the random seed. This function is
2083 designed to be more dependable than invoking /dev/urandom directly.
2084 OpenSSL and OpenNTPD currently support this function.
2086 Most people will answer N.
2088 config ARC4RANDOM_USES_NODEV
2089 bool "Do not use /dev/urandom with arc4random()"
2090 depends on UCLIBC_HAS_ARC4RANDOM
2092 Answer Y to use gettimeofday(2) and getpid(2) exclusively for
2093 arc4random(). This is not a bad idea for a diskless system, but
2094 it uses a lot of syscalls to stir each array element.
2096 Most people will answer N.
2101 config UCLIBC_HAS_SSP
2102 bool "Support for GCC stack smashing protector"
2103 depends on !HAVE_NO_SSP
2105 Add code to support GCC's -fstack-protector[-all] option to uClibc.
2106 This requires GCC 4.1 or newer. GCC does not have to provide libssp,
2107 the needed functions are added to ldso/libc instead.
2109 GCC's stack protector is a reimplementation of IBM's propolice.
2110 See http://www.trl.ibm.com/projects/security/ssp/ and
2111 http://www.linuxfromscratch.org/hints/downloads/files/ssp.txt
2114 Note that NOEXECSTACK on a kernel with address space randomization
2115 is generally sufficient to prevent most buffer overflow exploits
2116 without increasing code size. This option essentially adds debugging
2119 Most people will answer N.
2121 config SSP_QUICK_CANARY
2122 bool "Use simple guard values without accessing /dev/urandom"
2123 depends on UCLIBC_HAS_SSP
2125 Use gettimeofday(2) to define the __guard without accessing
2127 WARNING: This makes smashing stack protector vulnerable to timing
2129 Most people will answer N.
2132 prompt "Propolice protection blocking signal"
2133 depends on UCLIBC_HAS_SSP
2135 default PROPOLICE_BLOCK_SEGV
2137 "abort" use SIGABRT to block offending programs.
2138 This is the default implementation.
2140 "segfault" use SIGSEGV to block offending programs.
2141 Use this for debugging.
2143 If unsure, answer "abort".
2145 config PROPOLICE_BLOCK_ABRT
2148 config PROPOLICE_BLOCK_SEGV
2153 config UCLIBC_BUILD_SSP
2154 bool "Build uClibc with -fstack-protector"
2155 depends on UCLIBC_HAS_SSP
2157 Build all uClibc libraries and executables with -fstack-protector,
2158 adding extra stack overflow checking to most uClibc functions.
2160 config UCLIBC_BUILD_RELRO
2161 bool "Build uClibc with linker option -z RELRO"
2162 depends on HAVE_SHARED
2165 Build all libraries and executables with "ld -z relro".
2167 This tells the linker to mark chunks of an executable or shared
2168 library read-only after applying dynamic relocations. (This comes
2169 up when a global const variable is initialized to the address of a
2170 function or the value of another global variable.)
2172 This is a fairly obscure option the ld man page doesn't even bother
2173 to document properly. It's a security paranoia issue that's more
2174 likely to consume memory (by allocating an extra page) rather than
2177 This is explained in more depth at
2178 http://www.airs.com/blog/archives/189
2180 Nobody is likely to care whether you say Y or N here.
2182 config UCLIBC_BUILD_NOW
2183 bool "Build uClibc with linker option -z NOW"
2184 depends on HAVE_SHARED
2186 Build all libraries and executables with "ld -z now".
2188 This tells the linker to resolve all symbols when the library is
2189 first loaded, rather than when each function is first called. This
2190 increases start-up latency by a few microseconds and may do
2191 unnecessary work (resolving symbols that are never used), but the
2192 realtime people like it for making microbenchmark timings slightly
2193 more predictable and in some cases it can be slightly faster due to
2194 CPU cache behavior (not having to fault the linker back in to do
2195 lazy symbol resolution).
2197 Most people can't tell the difference between selecting Y or N here.
2199 config UCLIBC_BUILD_NOEXECSTACK
2200 bool "Build uClibc with noexecstack marking"
2203 Mark all assembler files as noexecstack, which will mark uClibc
2204 as not requiring an executable stack. (This doesn't prevent other
2205 files you link against from claiming to need an executable stack, it
2206 just won't cause uClibc to request it unnecessarily.)
2208 This is a security thing to make buffer overflows harder to exploit.
2209 By itself, it's kind of useless, as Linus Torvalds explained in 1998:
2210 http://old.lwn.net/1998/0806/a/linus-noexec.html
2212 It only actually provides any security when combined with address
2213 space randomization, explained here: http://lwn.net/Articles/121845/
2215 Address space randomization is on by default in current linux
2216 kernels (although it can be disabled using the option
2219 You should probably say Y.
2223 menu "Development/debugging options"
2225 config CROSS_COMPILER_PREFIX
2226 string "Cross-compiling toolchain prefix"
2229 The prefix used to execute your cross-compiling toolchain. For
2230 example, if you run 'arm-linux-uclibc-gcc' to compile something,
2231 then enter 'arm-linux-uclibc-' here.
2233 config UCLIBC_EXTRA_CFLAGS
2234 string "Extra CFLAGS"
2237 Add any additional CFLAGS to be used to build uClibc.
2240 bool "Enable debugging symbols"
2241 select EXTRA_WARNINGS
2243 Say Y here if you wish to compile uClibc with debugging symbols.
2244 This will allow you to use a debugger to examine uClibc internals
2245 while applications are running. This increases the size of the
2246 library considerably and should only be used when doing development.
2247 If you are doing development and want to debug uClibc, answer Y.
2249 Otherwise, answer N.
2252 bool "Build pthread with debugging output"
2253 depends on UCLIBC_HAS_THREADS && UCLIBC_HAS_LINUXTHREADS
2255 Enable debug output in libpthread. This is only useful when doing
2256 development in libpthread itself.
2258 Otherwise, answer N.
2261 bool "Strip libraries and executables"
2265 Say Y here if you do wish to strip all uClibc libraries and
2266 executables. No stripping increases the size of the binaries
2267 considerably, but makes it possible to debug uClibc libraries.
2268 Most people will answer Y.
2271 bool "Build with run-time assertion testing"
2273 Say Y here to include runtime assertion tests.
2274 This enables runtime assertion testing in some code, which can
2275 increase the size of the library and incur runtime overhead.
2276 If you say N, then this testing will be disabled.
2278 config SUPPORT_LD_DEBUG
2279 bool "Build the shared library loader with debugging support"
2280 depends on HAVE_SHARED
2282 Answer Y here to enable all the extra code needed to debug the uClibc
2283 native shared library loader. The level of debugging noise that is
2284 generated depends on the LD_DEBUG environment variable... Just set
2285 LD_DEBUG to something like: 'LD_DEBUG=token1,token2,.. prog' to
2286 debug your application. Diagnostic messages will then be printed to
2289 For now these debugging tokens are available:
2290 detail provide more information for some options
2291 move display copy processing
2292 symbols display symbol table processing
2293 reloc display relocation processing; detail shows the
2295 nofixups never fixes up jump relocations
2296 bindings displays the resolve processing (function calls);
2297 detail shows the relocation patch
2298 all Enable everything!
2300 The additional environment variable:
2301 LD_DEBUG_OUTPUT=file
2302 redirects the diagnostics to an output file created using
2303 the specified name and the process id as a suffix.
2305 An excellent start is simply:
2306 $ LD_DEBUG=binding,move,symbols,reloc,detail ./appname
2307 or to log everything to a file named 'logfile', try this
2308 $ LD_DEBUG=all LD_DEBUG_OUTPUT=logfile ./appname
2310 If you are doing development and want to debug uClibc's shared library
2311 loader, answer Y. Mere mortals answer N.
2313 config SUPPORT_LD_DEBUG_EARLY
2314 bool "Build the shared library loader with early debugging support"
2315 depends on HAVE_SHARED
2317 Answer Y here to if you find the uClibc shared library loader is
2318 crashing or otherwise not working very early on. This is typical
2319 only when starting a new port when you haven't figured out how to
2320 properly get the values for argc, argv, environ, etc. This method
2321 allows a degree of visibility into the very early shared library
2322 loader initialization process. If you are doing development and want
2323 to debug the uClibc shared library loader early initialization,
2324 answer Y. Mere mortals answer N.
2326 config UCLIBC_MALLOC_DEBUGGING
2327 bool "Build malloc with debugging support"
2328 depends on MALLOC || MALLOC_STANDARD
2331 Answer Y here to compile extra debugging support code into malloc.
2332 Malloc debugging output may then be enabled at runtime using the
2333 MALLOC_DEBUG environment variable.
2335 The value of MALLOC_DEBUG should be an integer, which is interpreted
2336 as a bitmask with the following bits:
2337 1 - do extra consistency checking
2338 2 - output messages for malloc/free calls and OS
2340 4 - output messages for the `MMB' layer
2341 8 - output messages for internal malloc heap manipulation
2344 Because this increases the size of malloc appreciably (due to strings
2345 etc), you should say N unless you need to debug a malloc problem.
2347 config UCLIBC_HAS_BACKTRACE
2348 bool "Add support for application self-debugging"
2349 depends on HAVE_SHARED
2351 Answer Y here to compile support for application self-debugging that
2352 provides the following new functions:
2353 backtrace, backtrace_symbols, backtrace_symbols_fd
2355 The backtrace functionality is currently supported on some platforms, and it
2356 based on dwarf2 informations to properly work, so any application that
2357 want to use backtrace needs to be built with -fexceptions flag.
2359 The symbol names may be unavailable without the use of special linker
2360 options. For systems using the GNU linker, it is necessary to use the
2361 -rdynamic linker option too. Note that names of "static" functions are not
2362 exposed, and won't be available in the backtrace.
2365 string "Compiler Warnings"
2368 Set this to the set of compiler warnings you wish to see while compiling.
2370 config EXTRA_WARNINGS
2371 bool "Enable extra annoying warnings"
2373 If you wish to build with extra warnings enabled, say Y here.