2 .\" Copyright (c) 1998 John D. Polstra
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31 .Nd find the shared object containing a given address
37 .Fn dladdr "const void *addr" "Dl_info *info"
42 queries the dynamic linker for information about the shared object
43 containing the address
45 The information is returned in the structure specified by
47 The structure contains at least the following members:
48 .Bl -tag -width "XXXconst char *dli_fname"
49 .It Li "const char *dli_fname"
50 The pathname of the shared object containing the address.
51 .It Li "void *dli_fbase"
52 The base address at which the shared object is mapped into the
53 address space of the calling process.
54 .It Li "const char *dli_sname"
55 The name of the nearest run-time symbol with a value less than or
58 When possible, the symbol name is returned as it would appear in C
61 If no symbol with a suitable value is found, both this field and
65 .It Li "void *dli_saddr"
66 The value of the symbol returned in
73 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
95 In particular, the following bugs are present:
100 lies in the main executable rather than in a shared library, the
104 The pathname is taken directly from
106 of the calling process.
107 When executing a program specified by its
108 full pathname, most shells set
111 But this is not required of shells or guaranteed
112 by the operating system.
120 is a global function, its value may be an unpleasant surprise.
122 dynamically linked programs, the address of a global function is
123 considered to point to its program linkage table entry, rather than to
124 the entry point of the function itself.
125 This causes most global
126 functions to appear to be defined within the main executable, rather
127 than in the shared libraries where the actual code resides.
129 Returning 0 as an indication of failure goes against long-standing