2 .\" Copyright (c) 1998 John D. Polstra
3 .\" All rights reserved.
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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"
43 function queries the dynamic linker for information about the shared object
44 containing the address
46 The information is returned in the structure specified by
48 The structure contains at least the following members:
49 .Bl -tag -width "XXXconst char *dli_fname"
50 .It Li "const char *dli_fname"
51 The pathname of the shared object containing the address.
52 .It Li "void *dli_fbase"
53 The base address at which the shared object is mapped into the
54 address space of the calling process.
55 .It Li "const char *dli_sname"
56 The name of the nearest run-time symbol with a value less than or
59 When possible, the symbol name is returned as it would appear in C
62 If no symbol with a suitable value is found, both this field and
66 .It Li "void *dli_saddr"
67 The value of the symbol returned in
73 function is available only in dynamically linked programs.
75 If a mapped shared object containing
80 In that case, a message detailing the failure can be retrieved by
84 On success, a non-zero value is returned.
91 function first appeared in the Solaris operating system.
93 This implementation is bug-compatible with the Solaris
94 implementation. In particular, the following bugs are present:
99 lies in the main executable rather than in a shared library, the
102 may not be correct. The pathname is taken directly from
104 of the calling process. When executing a program specified by its
105 full pathname, most shells set
107 to the pathname. But this is not required of shells or guaranteed
108 by the operating system.
116 is a global function, its value may be an unpleasant surprise. In
117 dynamically linked programs, the address of a global function is
118 considered to point to its program linkage table entry, rather than to
119 the entry point of the function itself. This causes most global
120 functions to appear to be defined within the main executable, rather
121 than in the shared libraries where the actual code resides.
123 Returning 0 as an indication of failure goes against long-standing