---
name: "gcpDetach"
section: "3"
platform: "linux"
package: "libggigcp1-dev"
version: "1.0.2+dfsg1-2"
release: "Debian 6.0 (Squeeze)"
platforms: ["linux"]
url: "https://new.carta.tech/gcpInit"
---

# gcpDetach(3)

Initialize and uninitialize LibGGIGCP

Part of [gcpInit(3)](/gcpInit/3.md).

## NAME

**gcpInit**, **gcpExit**, **gcpAttach**, **gcpDetach** - Initialize and uninitialize LibGGIGCP

## SYNOPSIS

```
#include <ggi/gcp.h>
int gcpInit(void);
int gcpExit(void);
int gcpAttach(ggi_visual_t vis);
int gcpDetach(ggi_visual_t vis);
```

## DESCRIPTION

These are the standard LibGGI extension management functions for the LibGGIGCP extension. They allow initialization and deinitialization of the extension as a whole and of individual visuals.

**gcpInit** will initialize an instance of the LibGGIGCP extension and prepare it to attach to visuals.

**gcpAttach**, if successful, will allow LibGGIGCP functions to operate on the named visual.

**gcpDetach**, if successful, will clean up all resources involved in providing the named visual with the LibGGIGCP API.

**gcpExit** will free all resources associated with an instance of LibGGIGCP.

## RETURN VALUE

**gcpInit** returns **0** for OK, otherwise an `ggi-error(3)` code.

**gcpExit** returns:

- **0**

  after successfully cleaning up,

- **\>0**

  the number of 'open' **gcpInit** calls, if there has been more than one call to **gcpInit**. As **gcpInit** and **gcpExit** must be used in properly nested pairs, e.g. the first **gcpExit** after two **gcpInit**'s will return **1**.

- **\<0**

  `ggi-error(3)`, especially if more **gcpExit** calls have been done than **gcpInit** calls.

**gcpAttach** returns:

- **\>=0**

  the number LibGGIGCP has been attached to this visual, whereas 0 means the first time.

- **\<0**

  indicates an `ggi-error(3)`.

**gcpDetach** returns:

- **0**

  after successfully cleaning up,

- **\>0**

  the number of 'open' **gcpAttach** calls, if there has been more than one call to **gcpAttach**. As **gcpAttach** and **gcpDetach** must be used in properly nested pairs, e.g. the first **gcpDetach** after two **gcpInit**'s will return **1**.

- **\<0**

  `ggi-error(3)`, especially if more **gcpDetach** calls have been done than **gcpAttach** calls.

## EXAMPLES

```
ggi_visual_t vis;
ggiInit();
gcpInit();
vis = ggiOpen(NULL);
gcpAttach(vis);
/* ... */
gcpDetach(vis);
gcpExit();
ggiExit();
```