HP-UX Reference (11i v2 04/09) - 3 Library Functions A-M (vol 6)

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dlclose(3C) dlclose(3C)

NAME

dlclose - close a shared library

SYNOPSIS

cc [ﬂag ... ] ﬁle ...

-ldl [library] ...

#include <dlfcn.h>

int dlclose(void *handle);

DESCRIPTION

dlclose is one of a family of routines that give the user direct access to the dynamic linking facilities

(using the -ldl option on the compiler or

ld command line). dlclose disassociates a shared object

previously opened by

dlopen from the current process. Once an object has been closed using

dlclose,

its symbols are no longer available to

dlsym

. All objects loaded automatically as a result of invoking

dlopen on the referenced object (see dlopen(3C)) are also closed. handle is the value returned by a pre-

vious invocation of

dlopen.

MULTITHREAD USAGE

This routine is thread-safe.

Note: The 32-bit dynamic loader dld.sl serializes the loading and unloading of shared libraries in mul-

tithreaded applications using a pthread mutex lock. See the HP-UX Linker and Libraries Online User

Guide for more information.

RETURN VALUE

If the referenced object was successfully closed,

dlclose returns 0. If the object could not be closed, or

if handle does not refer to an open object, dlclose returns a non-0 value. More detailed diagnostic

information is available through dlerror.

WARNINGS

A successful invocation of

dlclose does not guarantee that the objects associated with handle have

actually been removed from the address space of the process. Objects loaded by one invocation of

dlopen

may also be loaded by another invocation of dlopen. The same object may also be opened multiple

times. An object is not removed from the address space until all references to that object through an

explicit dlopen invocation have been closed and all other objects implicitly referencing that object have

also been closed.

Once an object has been closed by

dlclose, referencing symbols contained in that object can cause

undeﬁned behavior.