DLCLOSE(3P)						     POSIX Programmer's Manual						       DLCLOSE(3P)

PROLOG

       This  manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (consult the correspond-
       ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

NAME

       dlclose -- close a symbol table handle

SYNOPSIS

       #include <dlfcn.h>

       int dlclose(void *handle);

DESCRIPTION

       The dlclose() function shall inform the system that the symbol table handle specified by handle is no longer needed by the application.

       An application writer may use dlclose() to make a statement of intent on the part of the process, but this statement does  not  create  any
       requirement upon the implementation. When the symbol table handle is closed, the implementation may unload the executable object files that
       were loaded by dlopen() when the symbol table handle was opened and those that were loaded by dlsym() when using the  symbol  table  handle
       identified by handle.

       Once  a	symbol	table  handle has been closed, an application should assume that any symbols (function identifiers and data object identi-
       fiers) made visible using handle, are no longer available to the process.

       Although a dlclose() operation is not required to remove any functions or data objects from the address space, neither is an implementation
       prohibited  from  doing so. The only restriction on such a removal is that no function nor data object shall be removed to which references
       have been relocated, until or unless all such references are removed. For instance, an executable object file 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
       relocatable objects--in such environments, an application may assume that no relocation, once made, shall be undone or  remade  unless  the
       executable object file containing the relocated object has itself been removed.

RETURN VALUE

       If  the	referenced symbol table handle was successfully closed, dlclose() shall return 0. If handle does not refer to an open symbol table
       handle or if the symbol table handle could not be closed, dlclose() shall return a non-zero value.  More  detailed  diagnostic  information
       shall be available through dlerror().

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       The following example illustrates use of dlopen() and dlclose():

	   #include <dlfcn.h>
	   int eret;
	   void *mylib;
	   ...
	   /* Open a dynamic library and then close it ... */
	   mylib = dlopen("mylib.so", RTLD_LOCAL | RTLD_LAZY);
	   ...
	   eret = dlclose(mylib);
	   ...

APPLICATION USAGE

       A  conforming  application should employ a symbol table handle returned from a dlopen() invocation only within a given scope bracketed by a
       dlopen() operation and the corresponding dlclose() operation. Implementations are free to use reference counting or other  techniques  such
       that  multiple calls to dlopen() referencing the same executable object file may return a pointer to the same data object as the symbol ta-
       ble handle.

       Implementations are also free to re-use a handle. For these reasons, the value of a handle must be treated as an opaque data  type  by  the
       application, used only in calls to dlsym() and dlclose().

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       dlerror(), dlopen(), dlsym()

       The Base Definitions volume of POSIX.1-2008, <dlfcn.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C)  2013  by	the  Institute	of
       Electrical and Electronics Engineers, Inc and The Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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 Stan-
       dard is the referee document. The original Standard can be obtained online at http://www.unix.org/online.html .

       Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE
/The Open Group						       2013							       DLCLOSE(3P)