2010 Khronos Group.
glGetActiveSubroutineUniformName 3G
glGetActiveSubroutineUniformName query the name of an active shader subroutine uniform

## C Specification

void `glGetActiveSubroutineUniformName` GLuint program GLenum shadertype GLuint index GLsizei bufsize GLsizei *length GLchar *name

## Parameters

program

  Specifies the name of the program containing the subroutine.

shadertype

  Specifies the shader stage from which to query for the subroutine parameter. shadertype must be one of `GL_VERTEX_SHADER`, `GL_TESS_CONTROL_SHADER`, `GL_TESS_EVALUATION_SHADER`, `GL_GEOMETRY_SHADER` or `GL_FRAGMENT_SHADER`.

index

  Specifies the index of the shader subroutine uniform.

bufsize

  Specifies the size of the buffer whose address is given in name.

length

  Specifies the address of a variable into which is written the number of characters copied into name.

name

  Specifies the address of a buffer that will receive the name of the specified shader subroutine uniform.

## Description

`glGetActiveSubroutineUniformName` retrieves the name of an active shader subroutine uniform. program contains the name of the program containing the uniform. shadertype specifies the stage for which which the uniform location, given by index, is valid. index must be between zero and the value of `GL_ACTIVE_SUBROUTINE_UNIFORMS` minus one for the shader stage.

The uniform name is returned as a null-terminated string in name. The actual number of characters written into name, excluding the null terminator is returned in length. If length is `NULL`, no length is returned. The maximum number of characters that may be written into name, including the null terminator, is specified by bufsize. The length of the longest subroutine uniform name in program and shadertype is given by the value of `GL_ACTIVE_SUBROUTINE_UNIFORM_MAX_LENGTH`, which can be queried with glGetProgramStage.

## Errors

`GL_INVALID_ENUM` is generated if shadertype or pname is not one of the accepted values.

`GL_INVALID_VALUE` is generated if index is greater than or equal to the value of `GL_ACTIVE_SUBROUTINES`.

`GL_INVALID_VALUE` is generated if program is not the name of an existing program object.

## Associated Gets

glGetProgramStage with argument `GL_ACTIVE_SUBROUTINE_UNIFORMS`

## See Also

glGetSubroutineIndex, glGetActiveSubroutineUniform, glGetProgramStage

## Copyright

Copyright 2010 Khronos Group. 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/.