ldopen(3X)              LIBRARY FUNCTIONS              ldopen(3X)



NAME
     ldopen, ldaopen - open a common object file for reading

SYNOPSIS
     #include <stdio.h>
     #include <filehdr.h>
     #include <syms.h>
     #include <ldfcn.h>

     LDFILE *ldopen (filename, ldptr)
     char *filename;
     LDFILE *ldptr;

     LDFILE *ldaopen (filename, oldptr)
     char *filename;
     LDFILE *oldptr;

     ld readst (ldptr, flags)
     LDFILE *ldptr;
     intflags;

DESCRIPTION
     Ldopen and ldclose(3X)  provide  uniform  access  to  simple
     object files and to object files that are members of archive
     files.  An archive of common object files can  be  processed
     as if it were a series of simple common object files.

     If ldptr has the value NULL, ldopen  opens  filename,  allo-
     cates  and  initializes  the LDFILE structure, and returns a
     pointer to the structure to the calling program.

     If ldptr is valid  and  TYPE(ldptr)  is  the  archive  magic
     number,  ldopen  reinitializes  the LDFILE structure for the
     next archive member of filename.

     Ldopen and ldclose work in concert.  Ldclose returns FAILURE
     only  when TYPE(ldptr) is the archive magic number and there
     is another file in the archive to be processed.   Only  then
     should ldopen be called with the current value of ldptr.  In
     all other cases, and particularly when  a  new  filename  is
     opened, ldopen should be called with a NULL ldptr argument.

     The following is a prototype  for  the  use  of  ldopen  and
     ldclose:











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ldopen(3X)              LIBRARY FUNCTIONS              ldopen(3X)



          /* for each filename to be processed */

          ldptr = NULL;
          do
               if ( (ldptr = ldopen(filename, ldptr)) != NULL )

               {
                    /* check magic number */
                    /* process the file */
               }
          } while (ldclose(ldptr) == FAILURE );

     If the value of oldptr is not NULL, ldaopen  opens  filename
     anew  and  allocates and initializes a new LDFILE structure,
     copying the fields from oldptr.  Ldaopen returns  a  pointer
     to  the  new LDFILE structure.  This new pointer is indepen-
     dent of the old pointer, oldptr.  The two  pointers  can  be
     used concurrently to read separate parts of the object file.
     For example, one pointer can be used  to  step  sequentially
     through  the  relocation information while the other is used
     to read indexed symbol table entries.

     Ldopen and ldaopen open filename for reading.   If  filename
     cannot  be opened or if memory for the LDFILE structure can-
     not be allocated, both functions return NULL.  A  successful
     open  does not ensure that the given file is a common object
     file or an archived object file.

     Ldopen causes the symbol table header  and  file  descriptor
     table to be read.  Further access, using ldptr, causes other
     appropriate sections of the symbol table  to  be  read  (for
     example,  if you call ldtbread, the symbols or externals are
     read).  To force sections fot eh  symbol  table  in  memory,
     call  ldreadst  with  ST_P*  constants  ORed  together  from
     st_support.h.

     The program must be loaded with the object file access  rou-
     tine library libmld.a.

SEE ALSO
     fopen(3S), ldclose(3X), ldfcn(4).














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