2 .\" Copyright (c) 1998 John D. Polstra
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26 .\" $FreeBSD: src/lib/libc/gen/dladdr.3,v 1.3.2.4 2003/03/15 15:11:05 trhodes Exp $
27 .\" $DragonFly: src/lib/libc/gen/dladdr.3,v 1.2 2003/06/17 04:26:42 dillon Exp $
34 .Nd find the shared object containing a given address
40 .Fn dladdr "const void *addr" "Dl_info *info"
45 queries the dynamic linker for information about the shared object
46 containing the address
48 The information is returned in the structure specified by
50 The structure contains at least the following members:
51 .Bl -tag -width "XXXconst char *dli_fname"
52 .It Li "const char *dli_fname"
53 The pathname of the shared object containing the address.
54 .It Li "void *dli_fbase"
55 The base address at which the shared object is mapped into the
56 address space of the calling process.
57 .It Li "const char *dli_sname"
58 The name of the nearest run-time symbol with a value less than or
61 When possible, the symbol name is returned as it would appear in C
64 If no symbol with a suitable value is found, both this field and
68 .It Li "void *dli_saddr"
69 The value of the symbol returned in
76 is available only in dynamically linked programs.
78 If a mapped shared object containing
83 In that case, a message detailing the failure can be retrieved by
87 On success, a non-zero value is returned.
94 function first appeared in the Solaris operating system.
96 This implementation is bug-compatible with the Solaris
97 implementation. In particular, the following bugs are present:
102 lies in the main executable rather than in a shared library, the
105 may not be correct. The pathname is taken directly from
107 of the calling process. When executing a program specified by its
108 full pathname, most shells set
110 to the pathname. But this is not required of shells or guaranteed
111 by the operating system.
119 is a global function, its value may be an unpleasant surprise. In
120 dynamically linked programs, the address of a global function is
121 considered to point to its program linkage table entry, rather than to
122 the entry point of the function itself. This causes most global
123 functions to appear to be defined within the main executable, rather
124 than in the shared libraries where the actual code resides.
126 Returning 0 as an indication of failure goes against long-standing