HP-UX Reference (11i v2 04/09) - 3 Library Functions N-Z (vol 7)

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shl_load_pa(3X) shl_load_pa(3X)
(For PA-RISC Systems)
};
The type field in the return structure can have the values
TYPE_PROCEDURE
,orTYPE_DATA.On
PA-RISC 32i-bit systems, you can also have the values
TYPE_STORAGE or TYPE_TSTORAGE
.
These are a subset of
TYPE_DATA. The value and handle fields are only valid if export symbols are
requested and the
NO_VALUES flag is not specified. The value field contains the address of the
symbol, while the handle field is the handle of the library that defined the symbol, or NULL for
symbols defined via the
shl_definesym()
routine and is useful in conjunction with the
GLOBAL_VALUES flag.
If successful,
shl_getsymbols()
returns the number of symbols found; otherwise it returns −1.
shl_unload()
Can be used to detach a shared library from the process. The handle argument should be the han-
dle returned from a previous call to
shl_load(). On PA-RISC 64-bit systems, you can also get
the handle from a call to
dlopen()
. shl_unload() returns 0 if successful; otherwise −1is
returned. Any initializers registered with the library are called before detachment. All explicitly
loaded libraries are detached automatically on process termination.
The same shared library can be opened multiple times. On PA-RISC 32-bit systems,
shl_unload
unloads the shared library regardless of whether there are other references to it through other load
invocations or through implicit references from other shared libraries. No reference count is kept.
On PA-RISC 64-bit systems, a reference counter is kept for each loaded shared library, like the
behavior of dlopen(3C) and dlclose (3C). shl_unload does not remove the shared library from the
address space until all references to that shared library have been removed.
shl_get()
Returns information about currently loaded libraries, including those loaded implicitly at startup
time. The index argument is the ordinal position of the shared library in the shared library search
list for the process. A subsequent call to shl_unload() or dlclose() decrements the index
values of all libraries having an index greater than the unloaded library. The index value −1 refers
to the dynamic loader and the index value −2 refers to the program file itself. The desc argument is
used to return a pointer to a statically allocated buffer containing a descriptor for the shared library.
The format of the descriptor is implementation dependent; to examine its format, look at the con-
tents of file
/usr/include/dl.h
. Information common to all implementations includes the
library handle, pathname, and the range of addresses the library occupies. The buffer for the
descriptor used by
shl_get() is static; the contents should be copied elsewhere before a subse-
quent call to the routine. The routine returns 0 normally, or −1 if an invalid index is given.
shl_gethandle()
Returns information about the library specified by the handle argument. The special handle
PROG_HANDLE can be used to refer to the program itself. The descriptor returned is the same as
the one returned by the shl_get() routine. The buffer for the descriptor used by
shl_gethandle() is static; the contents should be copied elsewhere before a subsequent call to
the routine. The routine returns 0 normally, or −1 on error.
shl_get_r()
This is a reentrant version of shl_get(). The desc argument must point to a buffer of enough
user-defined storage to be filled with the library descriptor described in /usr/include/dl.h.
Its semantics are otherwise identical to
shl_get().
shl_gethandle_r()
This is a reentrant version of shl_gethandle(). The desc argument must point to a buffer of
enough user-defined storage to be filled with the library descriptor described in
/usr/include/dl.h. Its semantics are otherwise identical to shl_gethandle()
.
dld_getenv()
Informs the dynamic loader that the environment variable SHLIB_PATH has been modified since
program startup and the new value should be used for subsequent calls to shl_load().
DIAGNOSTICS
If a library cannot be loaded, shl_load() returns NULL and sets errno to indicate the error. This
includes trying to shl_load() a library containing thread local storage. All other functions return −1
on error and set errno.
Section 3−−978 Hewlett-Packard Company − 4 − HP-UX 11i Version 2: September 2004