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Command: ldopen | Section: 3 | Source: Digital UNIX | File: ldopen.3.gz
ldopen(3) Library Functions Manual ldopen(3)
NAME
ldopen, ldaopen - open a common object file for reading
LIBRARY
libmld.a
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;
ldreadst (ldptr, flags)
LDFILE *ldptr;
int flags;
DESCRIPTION
The ldopen and ldclose(3) routines provide uniform access to simple ob-
ject 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, allocates and ini-
tializes 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 file-
name.
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 ar-
gument.
The following is a prototype for the use of ldopen and ldclose: /* 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 al-
locates and initializes a new LDFILE structure, copying the fields from
oldptr. ldaopen returns a pointer to the new LDFILE structure. This
new pointer is independent of the old pointer, oldptr. The two point-
ers 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.
The ldopen function and ldaopen open filename for reading. If filename
cannot be opened or if memory for the LDFILE structure cannot be allo-
cated, both functions return NULL. A successful open does not ensure
that the given file is a common object file or an archived object file.
The ldopen function causes the symbol table header and file descriptor
table to be read. Further access, using ldptr, causes other appropri-
ate sections of the symbol table to be read (for example, if you call
ldtbread, the symbols or externals are read). To force sections for
the symbol table in memory, call ldreadst with ST_P* constants ORed to-
gether from st_support.h.
The program must be loaded with the object file access routine library
libmld.a.
RELATED INFORMATION
fopen(3), ldclose(3), ldfcn(4). delim off
ldopen(3)