glGetActiveUniformsiv 3G
glGetActiveUniformsiv Returns information about several active uniform variables for the specified program object

## C Specification

void `glGetActiveUniformsiv` GLuint program GLsizei uniformCount const GLuint *uniformIndices GLenum pname GLint *params

## Parameters

program

  Specifies the program object to be queried.

uniformCount

  Specifies both the number of elements in the array of indices uniformIndices and the number of parameters written to params upon successful return.

uniformIndices

  Specifies the address of an array of uniformCount integers containing the indices of uniforms within program whose parameter pname pname.

pname

  Specifies the property of the each uniform in uniformIndices that should be written into the corresponding element of params.

params

  Specifies the address of an array of uniformCount integers which are to receive the value of pname for each uniform in uniformIndices.

## Description

`glGetActiveUniformsiv` queries the value of the parameter named pname for each of the uniforms within program whose indices are specified in the array of uniformCount unsigned integers uniformIndices. Upon success, the value of the parameter for each uniform is written into the corresponding entry in the array whose address is given in params. If an error is generated, nothing is written into params.

If pname is `GL_UNIFORM_TYPE`, then an array identifying the types of uniforms specified by the corresponding array of uniformIndices is returned. The returned types can be any of the values from the following table:

Returned Symbolic Contant | Shader Uniform Type
--- | ---
`GL_FLOAT` | `float`
`GL_FLOAT_VEC2` | `vec2`
`GL_FLOAT_VEC3` | `vec3`
`GL_FLOAT_VEC4` | `vec4`
`GL_INT` | `int`
`GL_INT_VEC2` | `ivec2`
`GL_INT_VEC3` | `ivec3`
`GL_INT_VEC4` | `ivec4`
`GL_UNSIGNED_INT` | `unsigned int`
`GL_UNSIGNED_INT_VEC2` | `uvec2`
`GL_UNSIGNED_INT_VEC3` | `uvec3`
`GL_UNSIGNED_INT_VEC4` | `uvec4`
`GL_BOOL` | `bool`
`GL_BOOL_VEC2` | `bvec2`
`GL_BOOL_VEC3` | `bvec3`
`GL_BOOL_VEC4` | `bvec4`
`GL_FLOAT_MAT2` | `mat2`
`GL_FLOAT_MAT3` | `mat3`
`GL_FLOAT_MAT4` | `mat4`
`GL_FLOAT_MAT2x3` | `mat2x3`
`GL_FLOAT_MAT2x4` | `mat2x4`
`GL_FLOAT_MAT3x2` | `mat3x2`
`GL_FLOAT_MAT3x4` | `mat3x4`
`GL_FLOAT_MAT4x2` | `mat4x2`
`GL_FLOAT_MAT4x3` | `mat4x3`
`GL_SAMPLER_1D` | `sampler1D`
`GL_SAMPLER_2D` | `sampler2D`
`GL_SAMPLER_3D` | `sampler3D`
`GL_SAMPLER_CUBE` | `samplerCube`
`GL_SAMPLER_1D_SHADOW` | `sampler1DShadow`
`GL_SAMPLER_2D_SHADOW` | `sampler2DShadow`
`GL_SAMPLER_1D_ARRAY` | `sampler1DArray`
`GL_SAMPLER_2D_ARRAY` | `sampler2DArray`
`GL_SAMPLER_1D_ARRAY_SHADOW` | `sampler1DArrayShadow`
`GL_SAMPLER_2D_ARRAY_SHADOW` | `sampler2DArrayShadow`
`GL_SAMPLER_2D_MULTISAMPLE` | `sampler2DMS`
`GL_SAMPLER_2D_MULTISAMPLE_ARRAY` | `sampler2DMSArray`
`GL_SAMPLER_CUBE_SHADOW` | `samplerCubeShadow`
`GL_SAMPLER_BUFFER` | `samplerBuffer`
`GL_SAMPLER_2D_RECT` | `sampler2DRect`
`GL_SAMPLER_2D_RECT_SHADOW` | `sampler2DRectShadow`
`GL_INT_SAMPLER_1D` | `isampler1D`
`GL_INT_SAMPLER_2D` | `isampler2D`
`GL_INT_SAMPLER_3D` | `isampler3D`
`GL_INT_SAMPLER_CUBE` | `isamplerCube`
`GL_INT_SAMPLER_1D_ARRAY` | `isampler1DArray`
`GL_INT_SAMPLER_2D_ARRAY` | `isampler2DArray`
`GL_INT_SAMPLER_2D_MULTISAMPLE` | `isampler2DMS`
`GL_INT_SAMPLER_2D_MULTISAMPLE_ARRAY` | `isampler2DMSArray`
`GL_INT_SAMPLER_BUFFER` | `isamplerBuffer`
`GL_INT_SAMPLER_2D_RECT` | `isampler2DRect`
`GL_UNSIGNED_INT_SAMPLER_1D` | `usampler1D`
`GL_UNSIGNED_INT_SAMPLER_2D` | `usampler2D`
`GL_UNSIGNED_INT_SAMPLER_3D` | `usampler3D`
`GL_UNSIGNED_INT_SAMPLER_CUBE` | `usamplerCube`
`GL_UNSIGNED_INT_SAMPLER_1D_ARRAY` | `usampler2DArray`
`GL_UNSIGNED_INT_SAMPLER_2D_ARRAY` | `usampler2DArray`
`GL_UNSIGNED_INT_SAMPLER_2D_MULTISAMPLE` | `usampler2DMS`
`GL_UNSIGNED_INT_SAMPLER_2D_MULTISAMPLE_ARRAY` | `usampler2DMSArray`
`GL_UNSIGNED_INT_SAMPLER_BUFFER` | `usamplerBuffer`
`GL_UNSIGNED_INT_SAMPLER_2D_RECT` | `usampler2DRect`

If pname is `GL_UNIFORM_SIZE`, then an array identifying the size of the uniforms specified by the corresponding array of uniformIndices is returned. The sizes returned are in units of the type returned by a query of `GL_UNIFORM_TYPE`. For active uniforms that are arrays, the size is the number of active elements in the array; for all other uniforms, the size is one.

If pname is `GL_UNIFORM_NAME_LENGTH`, then an array identifying the length, including the terminating null character, of the uniform name strings specified by the corresponding array of uniformIndices is returned.

If pname is `GL_UNIFORM_BLOCK_INDEX`, then an array identifying the the uniform block index of each of the uniforms specified by the corresponding array of uniformIndices is returned. The uniform block index of a uniform associated with the default uniform block is -1.

If pname is `GL_UNIFORM_OFFSET`, then an array of uniform buffer offsets is returned. For uniforms in a named uniform block, the returned value will be its offset, in basic machine units, relative to the beginning of the uniform block in the buffer object data store. For uniforms in the default uniform block, -1 will be returned.

If pname is `GL_UNIFORM_ARRAY_STRIDE`, then an array identifying the stride between elements, in basic machine units, of each of the uniforms specified by the corresponding array of uniformIndices is returned. The stride of a uniform associated with the default uniform block is -1. Note that this information only makes sense for uniforms that are arrays. For uniforms that are not arrays, but are declared in a named uniform block, an array stride of zero is returned.

If pname is `GL_UNIFORM_MATRIX_STRIDE`, then an array identifying the stride between columns of a column-major matrix or rows of a row-major matrix, in basic machine units, of each of the uniforms specified by the corresponding array of uniformIndices is returned. The matrix stride of a uniform associated with the default uniform block is -1. Note that this information only makes sense for uniforms that are matrices. For uniforms that are not matrices, but are declared in a named uniform block, a matrix stride of zero is returned.

If pname is `GL_UNIFORM_IS_ROW_MAJOR`, then an array identifying whether each of the uniforms specified by the corresponding array of uniformIndices is a row-major matrix or not is returned. A value of one indicates a row-major matrix, and a value of zero indicates a column-major matrix, a matrix in the default uniform block, or a non-matrix.

## Errors

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

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

`GL_INVALID_VALUE` is generated if uniformCount is greater than or equal to the value of `GL_ACTIVE_UNIFORMS` for program.

`GL_INVALID_ENUM` is generated if pname is not an accepted token.

## Associated Gets

glGet with argument `GL_MAX_VERTEX_UNIFORM_COMPONENTS`, `GL_MAX_GEOMETRY_UNIFORM_COMPONENTS`, `GL_MAX_FRAGMENT_UNIFORM_COMPONENTS`, `GL_MAX_COMBINED_VERTEX_UNIFORM_COMPONENTS`, `GL_MAX_COMBINED_GEOMETRY_UNIFORM_COMPONENTS`, `GL_MAX_COMBINED_FRAGMENT_UNIFORM_COMPONENTS`.

glGetProgram with argument `GL_ACTIVE_UNIFORMS` or `GL_ACTIVE_UNIFORM_MAX_LENGTH`.

glIsProgram

## See Also

glGetUniform, glGetActiveUniform, glGetUniformLocation, glLinkProgram, glUniform, glUseProgram

## Copyright

Copyright 2011 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/.