ldopen, ldaopen - open a common object file for reading
#include <stdio.h> #include <filehdr.h> #include <syms.h> #include
LDFILE *ldptr ); LDFILE *ldaopen(
LDFILE *oldptr ); ldreadst(
int flags );
The ldopen() and ldclose() routines 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, allocates and
initializes the LDFILE structure, and returns a pointer to the struc‐
ture 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‐
The ldopen() and ldclose() functions 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 ldptr argument.
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 again 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 independent 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 sym‐
bol table entries.
The ldopen() and ldaopen() functions open filename for reading. If
filename cannot be opened or if memory for the LDFILE structure cannot
be allocated, both functions return NULL. A successful open does not
ensure that the given file is a common object file or an archived
The ldopen() function causes the symbol table header and file descrip‐
tor table to be read. Further access, by 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 sec‐
tions for the symbol table in memory, call ldreadst() with ST_P* con‐
stants ORed together from st_support.h.
The program must be loaded with the object file access routine library
SEE ALSOfopen(3), ldclose(3), ldfcn(4)ldopen(3)