---
name: "PkgRequire"
section: "3tcl"
platform: "linux"
package: "tcl8.3-doc"
version: "8.3.5-13"
release: "Debian 5.0 (Lenny)"
platforms: ["linux"]
url: "https://new.carta.tech/PkgRequire/3tcl"
---

# PkgRequire(3tcl)

package version control

```

```

## NAME

Tcl\_PkgRequire, Tcl\_PkgRequireEx, Tcl\_PkgPresent, Tcl\_PkgPresentEx, Tcl\_PkgProvide, Tcl\_PkgProvideEx - package version control

## SYNOPSIS

```
#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)
```

## ARGUMENTS

- 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.

  ```

  ```

## 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.

## KEYWORDS

package, present, provide, require, version