Originální popis anglicky:
dlclose - close a dlopen object
Návod, kniha: POSIX Programmer's Manual
#include <dlfcn.h>
int dlclose(void *
handle);
The
dlclose() function shall inform the system that the object referenced
by a
handle returned from a previous
dlopen() invocation is no
longer needed by the application.
The use of
dlclose() reflects a statement of intent on the part of the
process, but does not create any requirement upon the implementation, such as
removal of the code or symbols referenced by
handle. Once an object has
been closed using
dlclose() an application should assume that its
symbols are no longer available to
dlsym(). All objects loaded
automatically as a result of invoking
dlopen() on the referenced object
shall also be closed if this is the last reference to it.
Although a
dlclose() operation is not required to remove structures from
an address space, neither is an implementation prohibited from doing so. The
only restriction on such a removal is that no object shall be removed to which
references have been relocated, until or unless all such references are
removed. For instance, an object that had been loaded with a
dlopen()
operation specifying the RTLD_GLOBAL flag might provide a target for dynamic
relocations performed in the processing of other objects-in such environments,
an application may assume that no relocation, once made, shall be undone or
remade unless the object requiring the relocation has itself been removed.
If the referenced object was successfully closed,
dlclose() shall return
0. If the object could not be closed, or if
handle does not refer to an
open object,
dlclose() shall return a non-zero value. More detailed
diagnostic information shall be available through
dlerror().
No errors are defined.
The following sections are informative.
The following example illustrates use of
dlopen() and
dlclose():
...
/* Open a dynamic library and then close it ... */
#include <dlfcn.h>
void *mylib;
int eret;
mylib = dlopen("mylib.so", RTLD_LOCAL | RTLD_LAZY);
...
eret = dlclose(mylib);
...
A conforming application should employ a
handle returned from a
dlopen() invocation only within a given scope bracketed by the
dlopen() and
dlclose() operations. Implementations are free to
use reference counting or other techniques such that multiple calls to
dlopen() referencing the same object may return the same object for
handle. Implementations are also free to reuse a
handle. For
these reasons, the value of a
handle must be treated as an opaque
object by the application, used only in calls to
dlsym() and
dlclose().
None.
None.
dlerror() ,
dlopen() ,
dlsym() , the Base Definitions
volume of IEEE Std 1003.1-2001,
<dlfcn.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html
.
