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Section: C Library Functions (3)
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libst_intro, libst - Symbol table and object file access library  


#include <st.h>  


libst.a contains a collection of functions for accessing object file data and symbol table information. These functions effectively 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 functions do not provide access to 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 performance 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 procedures 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 instance. If a thread changes name-demangling for an object, then you should both set the name-demangling flag 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 synchronization.  


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
  #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");

     /* 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);

     /* 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]);
     /* 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);
           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);
              printf("   Procedure %s\n", pname);
              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 (0);


All functions indicate success by returning a value of 0 (zero). A positive 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 non-zero return status is the recommended method for detecting an error return from a libst function.  


header file that contains all definitions and function prototypes for libst.a functions header file that controls name-demangling operations for C++ objects  


Commands: atom(1)

Functions: st_addr_to_file(3), st_file_lang(3), st_obj_file_start(3), st_obj_open(3), st_objlist_append(3), st_proc_addr(3), st_sym_value(3),

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Time: 02:41:40 GMT, October 02, 2010