NAME

dladdr — find the image containing a given address

SYNOPSIS

#include <dlfcn.h>

int
dladdr(const void* addr, Dl_info* info);

DESCRIPTION

The dladdr() function queries dyld (the dynamic linker) for information about the image containing the address addr. The information is returned in the structure specified by info. The structure contains at least the following members:

const char* dli_fname: The pathname of the shared object containing the address.
void* dli_fbase: The base address (mach_header) at which the image is mapped into the address space of the calling process.
const char* dli_sname: The name of the nearest run-time symbol with a value less than or equal to addr.
void* dli_saddr: The value of the symbol returned in dli_sname.

The dladdr() function is available only in dynamically linked programs.

ERRORS

If an image containing addr cannot be found, dladdr() returns 0. On success, a non-zero value is returned.

If the image containing addr is found, but no nearest symbol was found, the dli_sname and dli_saddr fields are set to NULL.

HISTORY

The dladdr() function first appeared in the Solaris operating system.

AUTHORS

Mac OS X 10.3 incorporated the dlcompat package written by Jorge Acereda <jacereda@users.sourceforge.net> and Peter O'Gorman <ogorman@users.sourceforge.net>.

In Mac OS X 10.4, dlopen was rewritten to be a native part of dyld.

This man page was borrowed from FreeBSD and modified.

BUGS

This implementation is almost bug-compatible with the Solaris implementation. The following bugs are present:

Returning 0 as an indication of failure goes against long-standing Unix tradition.