src/internal/vis.h

   1 /* This file is only used if enabled in the build system, in which case it is
   2  * included automatically via command line options. It is not included
   3  * explicitly by any source files or other headers. Its purpose is to
   4  * override default visibilities to reduce the size and performance costs
   5  * of position-independent code. */
   6
   7 #ifndef CRT
   8 #ifdef SHARED
   9
  10 /* For shared libc.so, all symbols should be protected, but some toolchains
  11  * fail to support copy relocations for protected data, so exclude all
  12  * exported data symbols. */
  13
  14 __attribute__((__visibility__("default")))
  15 extern struct _IO_FILE *const stdin, *const stdout, *const stderr;
  16
  17 __attribute__((__visibility__("default")))
  18 extern int optind, opterr, optopt, optreset, __optreset, getdate_err, h_errno, daylight, __daylight, signgam, __signgam;
  19
  20 __attribute__((__visibility__("default")))
  21 extern long timezone, __timezone;
  22
  23 __attribute__((__visibility__("default")))
  24 extern char *optarg, **environ, **__environ, *tzname[2], *__tzname[2], *__progname, *__progname_full;
  25
  26 #pragma GCC visibility push(protected)
  27
  28 #elif defined(__PIC__)
  29
  30 /* If building static libc.a as position-independent code, try to make
  31  * everything hidden except possibly-undefined weak references. */
  32
  33 __attribute__((__visibility__("default")))
  34 extern void (*const __init_array_start)(), (*const __init_array_end)(),
  35         (*const __fini_array_start)(), (*const __fini_array_end)();
  36
  37 #pragma GCC visibility push(hidden)
  38
  39 #endif
  40 #endif