program
uniformCount
uniformIndices
pname
params
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_DOUBLE 
double

GL_DOUBLE_VEC2 
dvec2

GL_DOUBLE_VEC3 
dvec3

GL_DOUBLE_VEC4 
dvec4

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_DOUBLE_MAT2 
dmat2

GL_DOUBLE_MAT3 
dmat3

GL_DOUBLE_MAT4 
dmat4

GL_DOUBLE_MAT2x3 
dmat2x3

GL_DOUBLE_MAT2x4 
dmat2x4

GL_DOUBLE_MAT3x2 
dmat3x2

GL_DOUBLE_MAT3x4 
dmat3x4

GL_DOUBLE_MAT4x2 
dmat4x2

GL_DOUBLE_MAT4x3 
dmat4x3

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 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 atomic counter uniforms, the returned value will be its offset relative to the beginning of its active atomic counter buffer. For all other uniforms, 1 will be returned.
If pname is GL_UNIFORM_ARRAY_STRIDE, then an array identifying the stride between elements of each of the uniforms specified by the corresponding array of uniformIndices is returned. For uniforms in named uniform blocks and for uniforms declared as atomic counters, the stride is the difference, in basic machine units, of consecutive elements in an array, or zero for uniforms not declared as an array. For all other uniforms, a stride of 1 will be returned.
If pname is GL_UNIFORM_MATRIX_STRIDE, then an array identifying the stride between columns of a columnmajor matrix or rows of a rowmajor 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 rowmajor matrix or not is returned. A value of one indicates a rowmajor matrix, and a value of zero indicates a columnmajor matrix, a matrix in the default uniform block, or a nonmatrix.
If pname is GL_UNIFORM_ATOMIC_COUNTER_BUFFER_INDEX, then an array identifying the active atomic counter buffer index of each of the uniforms specified by the corresponding array of uniformIndices is returned. For uniforms other than atomic counters, the returned buffer index is 1. The returned indices may be passed to glGetActiveAtomicCounterBufferiv() to query the properties of the associated buffer, and not necessarily the binding point specified in the uniform declaration.
The double types, GL_DOUBLE, GL_DOUBLE_VEC2, GL_DOUBLE_VEC3, GL_DOUBLE_VEC4, GL_DOUBLE_MAT2, GL_DOUBLE_MAT3, GL_DOUBLE_MAT4, GL_DOUBLE_MAT2x3, GL_DOUBLE_MAT2x4, GL_DOUBLE_MAT3x2, GL_DOUBLE_MAT3x4, GL_DOUBLE_MAT4x2, and GL_DOUBLE_MAT4x3 are only available if the GL version is 4.1 or higher.
GL_UNIFORM_ATOMIC_COUNTER_BUFFER_INDEX is only accepted by pname if the GL version is 4.2 or higher.
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.
glGet() with argument GL_MAX_VERTEX_UNIFORM_COMPONENTS, GL_MAX_TESS_CONTROL_UNIFORM_COMPONENTS, GL_MAX_TESS_EVALUATION_UNIFORM_COMPONENTS, GL_MAX_GEOMETRY_UNIFORM_COMPONENTS, GL_MAX_FRAGMENT_UNIFORM_COMPONENTS, or GL_MAX_COMBINED_UNIFORM_COMPONENTS.
glGetProgram() with argument GL_ACTIVE_UNIFORMS or GL_ACTIVE_UNIFORM_MAX_LENGTH.

OpenGL Version
 
Function / Feature Name  2.0  2.1  3.0  3.1  3.2  3.3  4.0  4.1  4.2  4.3  4.4 
4.5

glGetActiveUniformsiv        ✔  ✔  ✔  ✔  ✔  ✔  ✔  ✔ 
✔

glGetUniform(), glGetActiveUniform(), glGetUniformLocation(), glLinkProgram(), glUniform(), glUseProgram()
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