## Name

glGetUniformIndices — retrieve the index of a named uniform block

## C Specification

`void glGetUniformIndices(` | GLuint program,
| GLsizei uniformCount,
| const GLchar **uniformNames,
| GLuint *uniformIndices`)`;

## Parameters

`program`

  Specifies the name of a program containing uniforms whose indices to query.

`uniformCount`

  Specifies the number of uniforms whose indices to query.

`uniformNames`

  Specifies the address of an array of pointers to buffers containing the names of the queried uniforms.

`uniformIndices`

  Specifies the address of an array that will receive the indices of the uniforms.

## Description

`glGetUniformIndices` retrieves the indices of a number of uniforms within `program`.

`program` must be the name of a program object for which the command glLinkProgram must have been called in the past, although it is not required that glLinkProgram must have succeeded. The link could have failed because the number of active uniforms exceeded the limit.

`uniformCount` indicates both the number of elements in the array of names `uniformNames` and the number of indices that may be written to `uniformIndices`.

`uniformNames` contains a list of `uniformCount` name strings identifying the uniform names to be queried for indices. For each name string in `uniformNames`, the index assigned to the active uniform of that name will be written to the corresponding element of `uniformIndices`. If a string in `uniformNames` is not the name of an active uniform, the special value `GL_INVALID_INDEX` will be written to the corresponding element of `uniformIndices`.

If an error occurs, nothing is written to `uniformIndices`.

## Errors

`GL_INVALID_OPERATION` is generated if `program` is not the name of a program object for which glLinkProgram has been called in the past.

## Notes

`glGetUniformIndices` is available only if the GL version is 3.1 or greater.

## See Also

glGetActiveUniform, glGetActiveUniformName, glLinkProgram

## 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/.