glGetProgram

3G

glGetProgramiv

Returns a parameter from a program object

# C Specification

            void glGetProgramiv
            GLuint program
            GLenum pname
            GLint *params

## Parameters

`program`

- Specifies the program object to be queried.

`pname`

- Specifies the object parameter. Accepted symbolic names are `GL_DELETE_STATUS`, `GL_LINK_STATUS`, `GL_VALIDATE_STATUS`, `GL_INFO_LOG_LENGTH`, `GL_ATTACHED_SHADERS`, `GL_ACTIVE_ATOMIC_COUNTER_BUFFERS`, `GL_ACTIVE_ATTRIBUTES`, `GL_ACTIVE_ATTRIBUTE_MAX_LENGTH`, `GL_ACTIVE_UNIFORMS`, `GL_ACTIVE_UNIFORM_BLOCKS`, `GL_ACTIVE_UNIFORM_BLOCK_MAX_NAME_LENGTH`, `GL_ACTIVE_UNIFORM_MAX_LENGTH`, `GL_COMPUTE_WORK_GROUP_SIZE` `GL_PROGRAM_BINARY_LENGTH`, `GL_TRANSFORM_FEEDBACK_BUFFER_MODE`, `GL_TRANSFORM_FEEDBACK_VARYINGS`, `GL_TRANSFORM_FEEDBACK_VARYING_MAX_LENGTH`, `GL_GEOMETRY_VERTICES_OUT`, `GL_GEOMETRY_INPUT_TYPE`, and `GL_GEOMETRY_OUTPUT_TYPE`.

`params`

- Returns the requested object parameter.

## Description

`glGetProgram` returns in `params` the value of a parameter for a specific program object. The following parameters are defined:

`GL_DELETE_STATUS`

- `params` returns `GL_TRUE` if `program` is currently flagged for deletion, and `GL_FALSE` otherwise.

`GL_LINK_STATUS`

- `params` returns `GL_TRUE` if the last link operation on `program` was successful, and `GL_FALSE` otherwise.

`GL_VALIDATE_STATUS`

- `params` returns `GL_TRUE` or if the last validation operation on `program` was successful, and `GL_FALSE` otherwise.

`GL_INFO_LOG_LENGTH`

- `params` returns the number of characters in the information log for `program` including the null termination character (i.e., the size of the character buffer required to store the information log). If `program` has no information log, a value of 0 is returned.

`GL_ATTACHED_SHADERS`

- `params` returns the number of shader objects attached to `program`.

`GL_ACTIVE_ATOMIC_COUNTER_BUFFERS`

- `params` returns the number of active attribute atomic counter buffers used by `program`.

`GL_ACTIVE_ATTRIBUTES`

- `params` returns the number of active attribute variables for `program`.

`GL_ACTIVE_ATTRIBUTE_MAX_LENGTH`

- `params` returns the length of the longest active attribute name for `program`, including the null termination character (i.e., the size of the character buffer required to store the longest attribute name). If no active attributes exist, 0 is returned.

`GL_ACTIVE_UNIFORMS`

- `params` returns the number of active uniform variables for `program`.

`GL_ACTIVE_UNIFORM_MAX_LENGTH`

- `params` returns the length of the longest active uniform variable name for `program`, including the null termination character (i.e., the size of the character buffer required to store the longest uniform variable name). If no active uniform variables exist, 0 is returned.

`GL_PROGRAM_BINARY_LENGTH`

- `params` returns the length of the program binary, in bytes that will be returned by a call to

  glGetProgramBinary

  . When a progam's `GL_LINK_STATUS` is `GL_FALSE`, its program binary length is zero.

`GL_COMPUTE_WORK_GROUP_SIZE`

- `params` returns an array of three integers containing the local work group size of the compute program as specified by its input layout qualifier(s). `program` must be the name of a program object that has been previously linked successfully and contains a binary for the compute shader stage.

`GL_TRANSFORM_FEEDBACK_BUFFER_MODE`

- `params` returns a symbolic constant indicating the buffer mode used when transform feedback is active. This may be `GL_SEPARATE_ATTRIBS` or `GL_INTERLEAVED_ATTRIBS`.

`GL_TRANSFORM_FEEDBACK_VARYINGS`

- `params` returns the number of varying variables to capture in transform feedback mode for the program.

`GL_TRANSFORM_FEEDBACK_VARYING_MAX_LENGTH`

- `params` returns the length of the longest variable name to be used for transform feedback, including the null-terminator.

`GL_GEOMETRY_VERTICES_OUT`

- `params` returns the maximum number of vertices that the geometry shader in `program` will output.

`GL_GEOMETRY_INPUT_TYPE`

- `params` returns a symbolic constant indicating the primitive type accepted as input to the geometry shader contained in `program`.

`GL_GEOMETRY_OUTPUT_TYPE`

- `params` returns a symbolic constant indicating the primitive type that will be output by the geometry shader contained in `program`.

## Notes

`GL_ACTIVE_UNIFORM_BLOCKS` and `GL_ACTIVE_UNIFORM_BLOCK_MAX_NAME_LENGTH` are available only if the GL version 3.1 or greater.

`GL_GEOMETRY_VERTICES_OUT`, `GL_GEOMETRY_INPUT_TYPE` and `GL_GEOMETRY_OUTPUT_TYPE` are accepted only if the GL version is 3.2 or greater.

`GL_COMPUTE_WORK_GROUP_SIZE` is accepted only if the GL version is 4.3 or greater.

If an error is generated, no change is made to the contents of `params`.

## Errors

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

`GL_INVALID_OPERATION` is generated if `program` does not refer to a program object.

`GL_INVALID_OPERATION` is generated if `pname` is `GL_GEOMETRY_VERTICES_OUT`, `GL_GEOMETRY_INPUT_TYPE`, or `GL_GEOMETRY_OUTPUT_TYPE`, and `program` does not contain a geometry shader.

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

`GL_INVALID_OPERATION` is generated if `pname` is `GL_COMPUTE_WORK_GROUP_SIZE` and `program` does not contain a binary for the compute shader stage.

## Associated Gets

glGetActiveAttrib

with argument `program`

glGetActiveUniform

with argument `program`

glGetAttachedShaders

with argument `program`

glGetProgramInfoLog

with argument `program`

glIsProgram

``

## See Also

glAttachShader

,

glCreateProgram

,

glDeleteProgram

,

glGetShader

,

glLinkProgram

,

glValidateProgram

## Copyright

Copyright 2003-2005 3Dlabs Inc. Ltd. Copyright 2010-2013 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/.