|
HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|
|
PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
|
|
|
DLCLOSE(3P) POSIX Programmer's Manual DLCLOSE(3P)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
dlclose — close a symbol table handle
#include <dlfcn.h>
int dlclose(void *handle);
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
identifiers) 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.
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().
No errors are defined.
The following sections are informative.
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);
...
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 table 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().
None.
None.
dlerror(3p), dlopen(3p), dlsym(3p)
The Base Definitions volume of POSIX.1‐2017, dlfcn.h(0p)
Portions of this text are reprinted and reproduced in electronic
form from IEEE Std 1003.1-2017, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The
Open Group Base Specifications Issue 7, 2018 Edition, Copyright
(C) 2018 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 .
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 2017 DLCLOSE(3P)
Pages that refer to this page: dlfcn.h(0p), dlerror(3p), dlopen(3p), dlsym(3p)
|
HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|