HP UX Software Transition Kit (STK) manual Shlt handle, Handle = Null, Shlfindsym&handle,foo

Parameters

Parameter		Definition
handle	A pointer to a shared library handle of the library to search for the symbol name sym. This handle
	can be obtained from the shl_get routine (“The shl_get and shl_get_r Routines” (page 175)). The
	handle parameter can also point to:
	NULL	If a pointer to NULL is specified, shl_findsym searches all loaded
		libraries for sym. If sym is found, shl_findsym sets handle to a
		pointer to the handle of the shared library containing sym. This is useful
		for determining which library a symbol resides in. For example, the
		following code sets handle to a pointer to the handle of the library
		containing symbol_foo
		shl_t handle;
		handle = NULL;
		shl_findsym(&handle,"_foo",...);
	PROG_HANDLE	This constant, defined in dl.h, tells shl_findsym to search for the
		symbol in the program itself. This way, any symbols exported from the
		program can be accessed explicitly.
sym	A null-terminated character string containing the name of the symbol to search for.
type	The type of symbol to look for. It must be one of the following values, defined in <dl.h>:
	TYPE_PROCEDURE	Looks for a function or procedure.
	TYPE_DATA	Looks for a symbol in the data segment (for example, variables).
	TYPE_UNDEFINED	Looks for any symbol.
	TYPE_STORAGE	Same as TYPE_DATA
value	A pointer in which shl_findsym stores the address of sym, if found.

Return Value

If successful, shl_findsym returns an integer (int) value zero. If shl_findsym cannot find sym, it returns -1and sets errno to zero. If any other errors occur, shl_findsym returns -1 and sets errno to one of these values (defined in <errno.h>):

Parameter	Definition
ENOEXEC	A format error was detected in the specified library.
ENOSYM	A symbol on which sym depends cannot be found.
EINVAL	The specified handle is invalid.

Description

To call a routine or access data in an explicitly loaded library, first get the address of the routine or data with shl_findsym. To call a routine in an explicitly loaded library:

1.Declare a pointer to a function of the same type as the function in the shared library

2.Using shl_findsym with the type parameter set to TYPE_PROCEDURE, find the symbol in the shared library and assign its address to the function pointer declared in Step 1

3.Call the pointer to the function obtained in Step 2, with the correct number and type of arguments

To access data in an explicitly loaded library:

The shl_load Shared Library Management Routines 173