Manual Pages for UNIX Operating System command usage for man dlclose

Standard C Library Functions                          dlclose(3C)



NAME
     dlclose - close a shared object

SYNOPSIS
     #include 

     int dlclose(void *handle);


DESCRIPTION
     The dlclose() function decrements the reference count of the
     supplied handle. This handle represents an executable object
     file and its dependencies, acquired from a previous call  to
     dlopen(). A handle that is no longer referenced is processed
     in an attempt to unload any objects that are associated with
     the  handle from the current process. An unreferenced handle
     is no longer available to dlsym().


     Any finalization code within an object is executed prior  to
     that  object  being  unloaded. Any routines registered by an
     object using atexit(3C) are  called  prior  to  that  object
     being unloaded. See NOTES.

RETURN VALUES
     If  the  handle  was  successfully  unreferenced,  dlclose()
     returns 0. If the handle is invalid, or an error occurred as
     a result of unloading an object, dlclose()  returns  a  non-
     zero  value.  Additional diagnostic information is available
     through dlerror().

USAGE
     The dlclose() function is one of a family of functions  that
     give  the  user direct access to the dynamic linking facili-
     ties. These facilities are available  to  dynamically-linked
     processes only. See the Linker and Libraries Guide.

ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:















SunOS 5.11          Last change: 1 March 2004                   1






Standard C Library Functions                          dlclose(3C)



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|
    | Standard                    | See standards(5).           |
    |_____________________________|_____________________________|


SEE ALSO
     ld(1),  ld.so.1(1),  atexit(3C),   dladdr(3C),   dldump(3C),
     dlerror(3C),  dlopen(3C),  dlsym(3C),  attributes(5),  stan-
     dards(5)


     Linker and Libraries Guide

NOTES
     A successful invocation of   dlclose()  does  not  guarantee
     that the objects associated with the handle are removed from
     the address space of the current  process.  Objects  can  be
     referenced  by  multiple  handles,  or  by other objects. An
     object is not removed from the address space of the  current
     process until all references to that object are removed.


     Once an object has been  closed  by  dlclose(),  referencing
     symbols   contained  in  that  object  can  cause  undefined
     behavior.


     As part of unloading an object, finalization code within the
     object  is called before the dlclose() returns. This finali-
     zation is user code, and as such, can  produce  errors  that
     can  not  be  caught  by  dlclose().  For example, an object
     loaded using RTLD_LAZY that attempts to call a function that
     can  not be located, results in process termination. Errone-
     ous programming practices within the finalization  code  can
     also  result  in  process  termination.  The runtime linkers
     debugging facility can offer help identifying these types of
     error. See the LD_DEBUG environment variable of ld.so.1(1).












SunOS 5.11          Last change: 1 March 2004                   2