dlclose - close a dlopen() object
void *handle );
Specifies a pointer to a global symbol object that is
returned from a call to dlopen().
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.
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
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().
No errors are defined.
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().
dlerror(3), dlopen(3), dlsym(3)
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