mirror of https://github.com/mkerrisk/man-pages
111 lines
3.8 KiB
Plaintext
111 lines
3.8 KiB
Plaintext
|
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
|
||
|
.TH "DLCLOSE" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
|
||
|
.\" dlclose
|
||
|
.SH NAME
|
||
|
dlclose \- close a dlopen object
|
||
|
.SH SYNOPSIS
|
||
|
.LP
|
||
|
\fB#include <dlfcn.h>
|
||
|
.br
|
||
|
.sp
|
||
|
int dlclose(void *\fP\fIhandle\fP\fB); \fP
|
||
|
\fB
|
||
|
.br
|
||
|
\fP
|
||
|
.SH DESCRIPTION
|
||
|
.LP
|
||
|
The \fIdlclose\fP() function shall inform the system that the object
|
||
|
referenced by a \fIhandle\fP returned from a previous \fIdlopen\fP()
|
||
|
invocation is no longer needed by the application.
|
||
|
.LP
|
||
|
The use of \fIdlclose\fP() 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 \fIhandle\fP. Once an object has been closed using
|
||
|
\fIdlclose\fP() an application should assume that its symbols are
|
||
|
no longer available to \fIdlsym\fP(). All objects loaded automatically
|
||
|
as a result of invoking \fIdlopen\fP() on the referenced object shall
|
||
|
also be closed if this is the last reference to
|
||
|
it.
|
||
|
.LP
|
||
|
Although a \fIdlclose\fP() 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 \fIdlopen\fP() 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.
|
||
|
.SH RETURN VALUE
|
||
|
.LP
|
||
|
If the referenced object was successfully closed, \fIdlclose\fP()
|
||
|
shall return 0. If the object could not be closed, or if
|
||
|
\fIhandle\fP does not refer to an open object, \fIdlclose\fP() shall
|
||
|
return a non-zero value. More detailed diagnostic
|
||
|
information shall be available through \fIdlerror\fP().
|
||
|
.SH ERRORS
|
||
|
.LP
|
||
|
No errors are defined.
|
||
|
.LP
|
||
|
\fIThe following sections are informative.\fP
|
||
|
.SH EXAMPLES
|
||
|
.LP
|
||
|
The following example illustrates use of \fIdlopen\fP() and \fIdlclose\fP():
|
||
|
.sp
|
||
|
.RS
|
||
|
.nf
|
||
|
|
||
|
\fB\&...
|
||
|
/* Open a dynamic library and then close it ... */
|
||
|
.sp
|
||
|
|
||
|
#include <dlfcn.h>
|
||
|
void *mylib;
|
||
|
int eret;
|
||
|
.sp
|
||
|
|
||
|
mylib = dlopen("mylib.so", RTLD_LOCAL | RTLD_LAZY);
|
||
|
\&...
|
||
|
eret = dlclose(mylib);
|
||
|
\&...
|
||
|
\fP
|
||
|
.fi
|
||
|
.RE
|
||
|
.SH APPLICATION USAGE
|
||
|
.LP
|
||
|
A conforming application should employ a \fIhandle\fP returned from
|
||
|
a \fIdlopen\fP()
|
||
|
invocation only within a given scope bracketed by the \fIdlopen\fP()
|
||
|
and \fIdlclose\fP()
|
||
|
operations. Implementations are free to use reference counting or
|
||
|
other techniques such that multiple calls to \fIdlopen\fP() referencing
|
||
|
the same object may return the same object for \fIhandle\fP.
|
||
|
Implementations are also free to reuse a \fIhandle\fP. For these reasons,
|
||
|
the value of a \fIhandle\fP must be treated as an
|
||
|
opaque object by the application, used only in calls to \fIdlsym\fP()
|
||
|
and
|
||
|
\fIdlclose\fP().
|
||
|
.SH RATIONALE
|
||
|
.LP
|
||
|
None.
|
||
|
.SH FUTURE DIRECTIONS
|
||
|
.LP
|
||
|
None.
|
||
|
.SH SEE ALSO
|
||
|
.LP
|
||
|
\fIdlerror\fP() , \fIdlopen\fP() , \fIdlsym\fP() , the Base Definitions
|
||
|
volume of IEEE\ Std\ 1003.1-2001, \fI<dlfcn.h>\fP
|
||
|
.SH COPYRIGHT
|
||
|
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 .
|