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dlclose(3)


NAME

  dlclose - close a dlopen() object


SYNOPSIS

  #include <dlfcn.h>

  int dlclose(
	  void *handle );


PARAMETERS

  handle
      Specifies a pointer to a global symbol object that is returned from a
      call to dlopen().


DESCRIPTION

  The dlclose() function is used to 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 requirements on the dynamic library
  loader, 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 are
  also closed.

  The dlclose() function deallocates the address space for the library
  corresponding to handle.  The results are undefined if any user function
  continues to call a symbol resolved in the address space of a library that
  has since been deallocated by dlclose().

  The dlclose() operation will not remove an object 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 option 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, will
  be undone or remade unless the object requiring the relocation has itself
  been removed.


NOTES

  The dlopen() and dlclose() routines might dynamically change the resolution
  of certain symbols referenced by a program or its shared library
  dependencies.	 The dlopen() routine might resolve symbols that were
  previously unresolved, and dlclose() might cause resolved symbols to become
  unresolved or to be reresolved to a different symbol definition.

  A portable application will employ a handle returned from a dlopen()
  invocation only within a given scope bracketed by the dlopen() and
  dlclose() operations. The dynamic library loader is 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. The
  dynamic library loader is also free to re-use 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().


ERRORS

  No errors are defined.


RETURN VALUE

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


SEE ALSO

  dlerror(3), dlopen(3), dlsym(3)

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