HP-UX Reference (11i v2 07/12) - 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);

Multithread Usage

This routine is thread-safe.

NOTE: The dynamic loader serializes the loading and unloading of shared libraries in multithreaded

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

User Guide for more information.

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 previous invocation of dlopen().

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().

ERRORS

If dlclose() fails, a subsequent call to dlerrno() returns one of the following values.

[RTLD_ERR_CANT_APPLY_RELOC] Cannot apply relocation in library.

[RTLD_ERR_DLCLOSE_REMAINING_DEP] Cannot close library due to remaining dependencies.

[RTLD_ERR_INV_HANDLE] Invalid handle.

[RTLD_ERR_NO_MEMORY] Out of memory.

[RTLD_ERR_SETCANCELSTATE_FAILED]

__thread_setcancelstate

failed on entry to

or exit from

dlclose().

[RTLD_ERR_SIGENABLE_FAILED]

sigenable failed on exit from dlclose().

[RTLD_ERR_SIGINHIBIT_FAILED]

siginhibit failed on entry to dlclose() .

[RTLD_ERR_UNKNOWN_HANDLE] Unknown handle.

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 dlo-

pen()

may also be loaded by another invocation of dlopen() . The same object may also be opened mul-

tiple 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.