NAME

       Tcl_PkgRequire,  Tcl_PkgRequireEx,  Tcl_PkgRequireProc,  Tcl_PkgPresent, Tcl_PkgPresentEx,
       Tcl_PkgProvide, Tcl_PkgProvideEx - package version control

SYNOPSIS

       #include <tcl.h>

       const char *
       Tcl_PkgRequire(interp, name, version, exact)

       const char *
       Tcl_PkgRequireEx(interp, name, version, exact, clientDataPtr)

       int
       Tcl_PkgRequireProc(interp, name, objc, objv, clientDataPtr)

       const char *
       Tcl_PkgPresent(interp, name, version, exact)

       const char *
       Tcl_PkgPresentEx(interp, name, version, exact, clientDataPtr)

       int
       Tcl_PkgProvide(interp, name, version)

       int
       Tcl_PkgProvideEx(interp, name, version, clientData)

ARGUMENTS

       Tcl_Interp *interp (in)           Interpreter where package is needed or available.

       const char *name (in)             Name of package.

       const char *version (in)          A version specification string as described for  package
                                         require.

       int exact (in)                    Non-zero   means   that   only  the  particular  version
                                         specified by version is  acceptable.   Zero  means  that
                                         newer  versions than version are also acceptable as long
                                         as they have the same major version number as version.

       const void *clientData (in)       Arbitrary value to be associated with the package.

       void *clientDataPtr (out)         Pointer to place to store the value associated with  the
                                         matching  package.  It is only changed if the pointer is
                                         not NULL and the function  completed  successfully.  The
                                         storage  can be any pointer type with the same size as a
                                         void pointer.

       int objc (in)                     Number of requirements.

       Tcl_Obj* objv[] (in)              Array of requirements.
_________________________________________________________________________________________________

DESCRIPTION

       These procedures provide C-level  interfaces  to  Tcl's  package  and  version  management
       facilities.

       Tcl_PkgRequire  is equivalent to the package require command, Tcl_PkgPresent is equivalent
       to the package present command, and Tcl_PkgProvide is equivalent to  the  package  provide
       command.

       See the documentation for the Tcl commands for details on what these procedures do.

       If  Tcl_PkgPresent  or  Tcl_PkgRequire  complete successfully they return a pointer to the
       version string for the version of the package that is provided in the  interpreter  (which
       may  be  different  than  version); if an error occurs they return NULL and leave an error
       message in the interpreter's result.

       Tcl_PkgProvide returns TCL_OK if it completes successfully; if an error occurs it  returns
       TCL_ERROR and leaves an error message in the interpreter's result.

       Tcl_PkgProvideEx,  Tcl_PkgPresentEx  and Tcl_PkgRequireEx allow the setting and retrieving
       of the client data associated with the package. In all other respects they are  equivalent
       to the matching functions.

       Tcl_PkgRequireProc  is  the  form  of  package require handling multiple requirements. The
       other forms are present for backward compatibility and translate their invocations to this
       form.

KEYWORDS

       package, present, provide, require, version

SEE ALSO

       package(3tcl), Tcl_StaticPackage(3tcl)