libst_intro(3)libst_intro(3)NAME
libst_intro, libst - symbol table and object file access library
SYNOPSIS
#include <st.h>
DESCRIPTION
The library libst.a contains a collection of functions for accessing
object file data and symbol table information. These functions effec‐
tively insulate the calling program from knowledge of the overall
structure of the object file. An object can be a file with a .o suffix,
a nonshared or call-shared executable, or a shared library. The libst
function can also be used to access objects in archive libraries.
The libst.a functions are particularly useful for developing tools that
must access file, procedure, symbol, or line number information. They
can assist in the development of Atom-based tools for application per‐
formance tuning and debugging. (See atom(1) for more information on the
Atom tool kit.)
The header file /usr/include/st.h contains all definitions and function
prototypes needed for utilizing libst.a functions. Some applications
may also need to include the <cmplrs/demangle_string.h> header file to
control name-demangling operations for C++ objects. By default, name
demangling is enabled by libst when an object is opened.
Functions allow you to manage both a single object and lists of
objects. Object lists are useful when a call-shared object and one or
more shared libraries that it uses must be available simultaneously.
Interface routines provide access to object file header information and
the symbol table. The symbol table contains information on source
files, procedures, symbols, symbol type/class/size information, and
lines. Address look-up routines are provided for text, data, and bss
addresses. Access is provided where applicable to obtain information at
the list, object, and source file level. For example, you can obtain
the number of procedures in an entire object or the number of proce‐
dures in a particular file. Functions return handles for objects,
files, procedures, and symbols.
libst functions are reentrant but not threadsafe. The calling program
must synchronize thread access to objects or lists of objects. You
should serialize access to an object list whenever an object is
appended or when the object list is closed. At the object level, you
should serialize calls to st_proc_sort, for example. If a thread
changes name demangling for an object, you should both set the name-
demangling option and perform the name translation before another
thread makes a name-translation call, such as st_sym_name. Generally,
most calls to libst are read requests and do not require synchroniza‐
tion.
RETURN VALUES
All functions indicate success by returning a value of 0 (zero). A pos‐
itive return value is an errno value from a system call. A negative
return value is a library error or informational code. The library
codes are documented in st.h.
Return parameters are set to 0 or -1 when an error occurs. Address
parameters are set to 0, and file and procedure handles are set to -1.
An exception to this occurs when a NULL pointer for the object or other
return parameter is input. In these cases, the return parameters will
be unchanged. A nonzero return status is the recommended method for
detecting an error return from a libst function.
EXAMPLES
The following code example shows how to use libst routines to list the
file and procedure names in an object file.
The build command for this program is:
cc -g test.c -o test -lst -lmld
This command ensures that libst will use any newer C++ demangler that
has been installed along with a C++ compiler. The program is linked as
a call-shared program, so the demangler in libmld.a loads libdeman‐
gle.so dynamically using ldopen(3), and it runs the shared library's
demangler if that one is newer. To link a non-shared program so that
libst uses a newer (or older) demangler in libdemangle.a, use this
build command:
cc -non_shared test.c -o test -lst -all -qldemangle -none -lmld
#include <st.h>
main(int argc, char **argv) {
st_status_t ret;
st_obj_t *obj;
st_file_t file;
st_proc_t proc;
unsigned int fcount;
unsigned int pcount;
char *fname;
char *pname;
st_bool_t stripped;
st_addr_t paddr;
int i, j;
if(argc < 2) {
printf("Usage: test object_name\n");
exit(1);
}
/* Open the object. For C++, name demangling is enabled
* when an object is successfully opened.
*/
if((ret = st_obj_open(&obj, argv[1], ST_RDONLY))) {
printf("open ret = %d\n",ret);
exit(1);
}
/* If the object is stripped, exit since no symbolic
* information is available.
*/
st_is_obj_stripped(obj, &stripped);
if(stripped) {
printf("Object %s is stripped\n", argv[1]);
exit(0);
}
/* Get handle for first file in the object and the count
* of files.
*/
st_obj_file_start(obj, &file);
st_obj_file_count(obj, &fcount);
/* Loop through the files in the object, printing the
* procedures contained in each. File names and static
* procedure names are unavailable for files that were not
* compiled with -g.
*/
for(i = 0; i < fcount; i++) {
st_is_file_locally_stripped(obj, file, &stripped);
if(stripped)
printf("File is locally stripped - name is unavailable:\n");
else {
st_file_name(obj, file, &fname);
printf("File %s:\n", fname);
}
/* Get handle for first procedure for this file, and the
* count of procedures in the file.
*/
st_file_proc_start(obj, file, &proc);
st_file_proc_count(obj, file, &pcount);
/* Loop through the procedures for the file, printing the
* procedure name if available. Static procedure names are not
* available, for example, if the file was not compiled with -g.
*/
for(j=0; j < pcount; j++) {
st_file_t fi;
char *fn;
/* If name lookup fails, get the procedure address */
if((ret = st_proc_name(obj, proc, &pname)))
st_proc_addr(obj, proc, &paddr);
if(!ret)
printf(" Procedure %s\n", pname);
else
printf(" Procedure at 0x%p\n",paddr);
st_file_proc_next(obj, file, proc, &proc);
}
st_obj_file_next(obj, file, &file);
}
ret = st_obj_close(obj);
if (ret) {
printf("close ret = %d\n",ret);
exit(1);
}
exit (0); }
FILES
Header file that contains all definitions and function prototypes for
libst.a functions Header file that controls name-demangling operations
for C++ objects
SEE ALSO
Commands: atom(1)
Functions: st_addr_to_file(3), st_cm_setup(3), st_file_lang(3),
st_get_known_versions(3), st_lang_str(3), st_obj_calls(3),
st_obj_file_start(3), st_obj_open(3), st_objlist_append(3),
st_proc_addr(3), st_pt_setup(3), st_strerror(3), st_sym_value(3)libst_intro(3)