dladdr(3C)

NAME
     dladdr - Translates address to symbolic information

SYNOPSIS
     cc [flags ...] [file ...]

     #include <dlfcn.h> int dladdr(void *address, Dl_info *dlip);

IMPLEMENTATION
     IRIX systems

DESCRIPTION
     dladdr() determines if the specified address is located within one of
     the mapped objects (either the executable or a DSO) that make up the
     current application address space.  If the address is within an
     object, the symbol table available to the run-time linker (rld(1)) is
     searched to locate the nearest symbol to the specified address.  The
     nearest symbol is one that has a value less than or equal to the
     required address.

     The Dl_info structure must be preallocated by the user.  The structure
     members are filled in by dladdr() based on the specified address.  The
     Dl_info structure contains at least the following members:

          const char * dli_fname;
          void       * dli_fbase;
          const char * dli_sname;
          void       * dli_saddr;

     The members are defined as follows:

     dli_fname
          Contains a pointer to the file name of the containing object.

     dli_fbase
          Contains the base address (in memory) of the containing object.

     dli_sname
          Contains a pointer to the nearest symbol name.  This symbol
          either has the same address or is the nearest symbol with a lower
          address.

     dli_saddr
          Contains the actual address of the above symbol.

     The following nonstandard field is in Dl_info:

     dli_version
          This is filled in with zero by dladdr().

NOTES
     If no symbol is found to describe the specified address, but the
     address is within a mapped-in object, the dli_sname and dli_saddr
     members are set to 0 by dladdr().

     The memory pointed to by dli_fname and dli_sname is within the mapped
     object. If the object is closed with dlclose(), the pointers become
     invalid.

     If the call is attempted on a system that does not have the supporting
     functionality, the following message will be emitted to /dev/tty by
     default, and the application will be terminated with a non-zero exit
     code:

          Fatal Error: _rld_new_interface: bad operation: 14

     Applications that might be executed on IRIX releases without the
     latest rld should first attempt the call in a separate small process.
     Define the environment variable _RLD_ARGS as the following to direct
     the rld message to disk, if its appearance on /dev/tty might be an
     annoyance:

          -log /tmp/rldmessage

     On a development system with dlfcn.h missing Dl_info and libc missing
     dladdr(), but with rld implementing _RLD_DLADDR, the following is a
     sample implementation that you might want to try.  This sample
     implementation is not guaranteed to work, because user applications
     and DSOs should not call _rld_new_interface, but it is provided with
     the hope that it will be useful.

          #include <rld_interface.h>
          #ifndef _RLD_INTERFACE_DLFCN_H_DLADDR
          #define _RLD_INTERFACE_DLFCN_H_DLADDR
          struct Dl_info {
              const char * dli_fname;
              void       * dli_fbase;
              const char * dli_sname;
              void       * dli_saddr;
              int          dli_version;
              int          dli_reserved1;
              long         dli_reserved[4];
          };
          #endif
          #define _RLD_DLADDR             14
          int dladdr(void *address, struct Dl_info *dl);

          int dladdr(void *address, struct Dl_info *dl)
          {
                  void *v;
                  v = _rld_new_interface(_RLD_DLADDR,address,dl);
                  return (int)v;
          }

DIAGNOSTICS
     The function returns zero if the address cannot be associated with a
     mapped-in object.  In such a case, the Dl_info fields are not touched.

     The function returns non-zero if it can be associated with a mapped-in
     object, and the Dl_info fields are updated.

SEE ALSO
     dlopen(3C), dlclose(3C), dlsym(3C), sgidlopen_version(3C),
     sgidlopen_verison(3C)
     rld(1)
     dso(5)

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