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 $
33 .Nd find the shared object containing a given address
39 .Fn dladdr "const void *addr" "Dl_info *info"
44 queries the dynamic linker for information about the shared object
45 containing the address
47 The information is returned in the structure specified by
49 The structure contains at least the following members:
50 .Bl -tag -width "XXXconst char *dli_fname"
51 .It Li "const char *dli_fname"
52 The pathname of the shared object containing the address.
53 .It Li "void *dli_fbase"
54 The base address at which the shared object is mapped into the
55 address space of the calling process.
56 .It Li "const char *dli_sname"
57 The name of the nearest run-time symbol with a value less than or
60 When possible, the symbol name is returned as it would appear in C
63 If no symbol with a suitable value is found, both this field and
67 .It Li "void *dli_saddr"
68 The value of the symbol returned in
75 is available only in dynamically linked programs.
77 If a mapped shared object containing
82 In that case, a message detailing the failure can be retrieved by
86 On success, a non-zero value is returned.
93 function first appeared in the Solaris operating system.
95 This implementation is bug-compatible with the Solaris
96 implementation. In particular, the following bugs are present:
101 lies in the main executable rather than in a shared library, the
104 may not be correct. The pathname is taken directly from
106 of the calling process. When executing a program specified by its
107 full pathname, most shells set
109 to the pathname. But this is not required of shells or guaranteed
110 by the operating system.
118 is a global function, its value may be an unpleasant surprise. In
119 dynamically linked programs, the address of a global function is
120 considered to point to its program linkage table entry, rather than to
121 the entry point of the function itself. This causes most global
122 functions to appear to be defined within the main executable, rather
123 than in the shared libraries where the actual code resides.
125 Returning 0 as an indication of failure goes against long-standing