Tcl_PkgRequire(), Tcl_PkgRequireEx(), Tcl_PkgPresent(), Tcl_PkgPresentEx(), Tcl_PkgProvide(), Tcl_PkgProvideEx()

package version control 

Tcl Library Procedures


#include <tcl.h>

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

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

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

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

int Tcl_PkgProvide(interp, name, version)

int Tcl_PkgProvideEx(interp, name, version, clientData)


Tcl_Interp *interp (in) 

Interpreter where package is needed or available.

char *name (in) 

Name of package.

char *version (in) 

A version string consisting of one or more decimal numbers separated by dots.

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.

ClientData clientData (in) 

Arbitrary value to be associated with the package.

ClientData *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.


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.


Windows 8.1. Windows Server 2012 R2. Windows 10. Windows Server 2016. Windows Server 2019. Windows 11. Windows Server 2022.


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