PROLOG

       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.

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  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.

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 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().

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       dlerror(), dlopen(), dlsym()

       The Base Definitions volume of POSIX.1‐2017, <dlfcn.h>

COPYRIGHT

       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(3POSIX)