dladdr.3c (2010 09)

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dladdr(3C) dladdr(3C)
NAME
dladdr() - get the symbolic information for an address
SYNOPSIS
cc [flag]... cfile ...
-ldl [library ]...
#include <dlfcn.h>
int dladdr(void *address, Dl_info *dlip);
Multithread Usage
This routine is thread-safe.
DESCRIPTION
dladdr() is one of a family of routines that give the user direct access to the dynamic linking facilities
(using the -ldl option on the compiler or
ld command line). dladdr() allows a process to obtain
information about the symbol that most closely defines a given address .
dladdr() determines whether
the specified address is located within one of the load modules (executable or shared libraries) that make
up the process’ address space. An address is deemed to fall within a load module when it is between the
base address at which the load module was mapped and the highest virtual address mapped for that load
module, inclusive. If a load module fits this criteria, its dynamic symbol table is searched to locate the
nearest symbol to the specified address . The nearest symbol is the one whose value is equal to, or closest
to but less than the specified address .
dlip is a pointer to a
Dl_info structure. The structure must be allocated by the user. The structure
members are set by dladdr() if the specified address falls within one of the load modules. The
Dl_info structure contains the following members:
struct {
const char *dli_fname;
void *dli_fbase;
const char *dli_sname;
void *dli_saddr;
size_t dli_size; /* ELF only */
int dli_bind; /* ELF only */
int dli_type;
};
The fields of the Dl_info structure contain the following:
dli_fname Pointer to the filename of the load module containing the address . The contents of
this memory location can change between calls to
dladdr().
dli_fbase Handle to the load module. This can be used as the first argument to
dlsym()
.
dli_sname Pointer to the name of the nearest symbol to the specified address . This symbol either
has the same address, or is the nearest symbol with a lower address. The contents of
this memory location can change between calls to
dladdr().
dli_saddr Actual address of the nearest symbol. For code symbols, it contains the address of the
OPD (Official Plabel Descriptor) for the nearest code symbol.
dli_size (ELF process only) Size of the nearest symbol as defined in the dynamic symbol table.
dli_bind (ELF process only) Binding attribute of the nearest symbol as defined in the dynamic
symbol table. The values for this are those used for a symbol’s binding in the ELF
symbol table (see
<elf.h>)
dli_type Type of the nearest symbol. For ELF process, this is the same as the value for type in
the dynamic symbol table. The values for this are those used for a symbol’s type in
the ELF symbol table (see
<elf.h>). For SOM process, this can have the value
TYPE_DATA or TYPE_PROCEDURE as defined in <dl.h>).
RETURN VALUE
If the specified address does not fall within one of the load modules,
0 is returned; the contents of the
Dl_info structure are not modified. Otherwise, a non-zero value is returned and the fields of the
Dl_info structure are set.
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1