LDOPEN(S) UNIX System V LDOPEN(S)
Name
ldopen, ldaopen - open a common object file for reading
Syntax
#include <stdio.h>
#include <filehdr.h>
#include <ldfcn.h>
LDFILE *ldopen (filename, ldptr)
char *filename;
LDFILE *ldptr;
LDFILE *ldaopen (filename, oldptr)
char *filename;
LDFILE *oldptr;
Description
The ldopen and ldclose(S) functions are designed to provide
uniform access to both simple object files and object files
that are members of archive files. Thus 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, then ldopen will open filename
and allocate and initialize the LDFILE structure, and return
a pointer to the structure to the calling program.
If ldptr is valid and if TYPE(ldptr) is the archive magic
number, ldopen will reinitialize the LDFILE structure for
the next archive member of filename.
The ldopen and ldclose(S) functions are designed to work in
concert. ldclose will return 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, in
particular whenever 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(S).
/* 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 will open
filename anew and allocate and initialize a new LDFILE
structure, copying the TYPE, OFFSET, and HEADER fields from
oldptr. ldaopen returns a pointer to the new LDFILE
structure. This new pointer is independent of the old
pointer, oldptr. The two pointers may be used concurrently
to read separate parts of the object file. For example, one
pointer may be used to step sequentially through the
relocation information, while the other is used to read
indexed symbol table entries.
Both ldopen and ldaopen open filename for reading. Both
functions return NULL if filename cannot be opened, or if
memory for the LDFILE structure cannot be allocated. A
successful open does not ensure that the given file is a
common object file or an archived object file.
The program must be loaded with the -lld flag.
See Also
fopen(S), ldclose(S), ldfcn(F)
(printed 6/20/89)