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Core in version 4.6
Core since version 3.1

glGetUniformBlockIndex: retrieve the index of a named uniform block

Function Definition

 GLuint glGetUniformBlockIndex(GLuint program​, const GLchar *uniformBlockName​);
Specifies the name of a program containing the uniform block.
Specifies the address an array of characters to containing the name of the uniform block whose index to retrieve.


glGetUniformBlockIndex retrieves the index of a uniform block 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.

uniformBlockName​ must contain a nul-terminated string specifying the name of the uniform block.

glGetUniformBlockIndex returns the uniform block index for the uniform block named uniformBlockName​ of program​. If uniformBlockName​ does not identify an active uniform block of program​, glGetUniformBlockIndex returns the special identifier, GL_INVALID_INDEX. Indices of the active uniform blocks of a program are assigned in consecutive order, beginning with zero.


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


glGetUniformBlockIndex is available only if the GL version is 3.1 or greater.

See Also

glGetActiveUniformBlockName, glGetActiveUniformBlock, glGetProgramResource, glUniformBlockBinding


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.