HP-UX Linker and Libraries User's Guide

The shared library's handle (type shl_t).handle
A character array containing the library's path name as specified at link time
or at explicit load time.
filename
A pointer to the shared library's initializer routine (see Initializers for Shared
Libraries. It is NULL if there is no initializer. This field is useful for calling the
initializer if it was disabled by the BIND_NOSTART flag to shl_load.
initializer
If the shared library has multiple initializers, this field is also set to NULL. Multiple
initializers can be found with shl_getsymbols, described later in this chapter.
This buffer is statically allocated. Therefore, if a program intends to use any of the members of the
structure, the program must make a copy of the structure before the next call to shl_get. Otherwise,
shl_get overwrites the static buffer when called again.
Return Value
If successful, shl_get returns an integer value 0. If the index value exceeds the number of
currently loaded libraries, shl_get returns -1 and sets errno to EINVAL.
Description
To obtain information on currently loaded libraries, use the shl_get function. If you are
programming in a threaded environment, use the thread-safe version shl_get_r which is the
same as shl_get in all other respects. (See Programming with Threads on HP-UX for more
information about threads.)
Other than obtaining interesting information, this routine is of little use to most programmers. A
typical use may be to display the names and starting/ending address of all shared libraries in a
process's virtual memory address space.
Example
The function show_loaded_libs shown below displays the name and start and end address of
the text and data/bss segments the library occupies in a process's virtual address space.
show_loaded_libs - Display Library Information
#include <stdio.h> /* contains standard I/O defs */
#include <dl.h> /* contains shared library type defs */
void show_loaded_libs(void)
{
int idx;
struct shl_descriptor *desc;
printf("SUMMARY of currently loaded libraries:\n");
printf("%-25s %10s %10s %10s %10s\n",
"___library___", "_tstart_", "__tend__", "_dstart_", "__dend__");
idx = 0;
for (idx = 0; shl_get(idx, &desc) != -1; idx++)
printf("%-25s %#10lx %#10lx %#10lx %#10lx\n",
desc->filename, desc->tstart, desc->tend, desc->dstart, desc->dend);
}
Calling this function from a C program compiled with shared libc and libdld produced the
following output:
SUMMARY of currently loaded libraries:
___library___ _tstart_ __tend__ _dstart_ __dend__
./a.out 0x1000 0x1918 0x40000000 0x40000200
/usr/lib/libdld.so 0x800ac800 0x800ad000 0x6df62800 0x6df63000
/usr/lib/libc.so 0x80003800 0x80091000 0x6df63000 0x6df85000
176 Shared Library Management Routines