glAttachShader
3G

# glAttachShader

Attaches a shader object to a program object

## C Specification

    		void glAttachShader
    		GLuint program
    		GLuint shader

## Parameters

`program`

  Specifies the program object to which a shader object will be attached.

`shader`

  Specifies the shader object that is to be attached.

## Description

In order to create an executable, there must be a way to specify the list of things that will be linked together. Program objects provide this mechanism. Shaders that are to be linked together in a program object must first be attached to that program object. `glAttachShader` attaches the shader object specified by `shader` to the program object specified by `program`. This indicates that `shader` will be included in link operations that will be performed on `program`.

All operations that can be performed on a shader object are valid whether or not the shader object is attached to a program object. It is permissible to attach a shader object to a program object before source code has been loaded into the shader object or before the shader object has been compiled. It is permissible to attach multiple shader objects of the same type because each may contain a portion of the complete shader. It is also permissible to attach a shader object to more than one program object. If a shader object is deleted while it is attached to a program object, it will be flagged for deletion, and deletion will not occur until glDetachShader is called to detach it from all program objects to which it is attached.

## Notes

`glAttachShader` is available only if the GL version is 2.0 or greater.

## Errors

`GL_INVALID_VALUE` is generated if either `program` or `shader` is not a value generated by OpenGL.

`GL_INVALID_OPERATION` is generated if `program` is not a program object.

`GL_INVALID_OPERATION` is generated if `shader` is not a shader object.

`GL_INVALID_OPERATION` is generated if `shader` is already attached to `program`.

`GL_INVALID_OPERATION` is generated if `glAttachShader` is executed between the execution of glBegin and the corresponding execution of glEnd.

## Associated Gets

glGetAttachedShaders with the handle of a valid program object

glIsProgram

glIsShader

## See Also

glCompileShader, glDetachShader, glLinkProgram, glShaderSource

## Copyright

Copyright 2003-2005 3Dlabs Inc. Ltd. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/.