shader: Specifies the shader object to be queried.
pname: Specifies the object parameter. Accepted symbolic names are Gl.SHADER_TYPE, Gl.DELETE_STATUS, Gl.COMPILE_STATUS, Gl.INFO_LOG_LENGTH, Gl.SHADER_SOURCE_LENGTH.
params: Returns the requested object parameter.

Gl.GetShader returns in params the value of a parameter for a specific shader object. The following parameters are defined:

Gl.SHADER_TYPE: params returns Gl.VERTEX_SHADER if shader is a vertex shader object, Gl.GEOMETRY_SHADER if shader is a geometry shader object, and Gl.FRAGMENT_SHADER if shader is a fragment shader object.
Gl.DELETE_STATUS: params returns Gl.TRUE if shader is currently flagged for deletion, and Gl.FALSE otherwise.
Gl.COMPILE_STATUS: params returns Gl.TRUE if the last compile operation on shader was successful, and Gl.FALSE otherwise.
Gl.INFO_LOG_LENGTH: params returns the number of characters in the information log for shader including the null termination character (i.e., the size of the character buffer required to store the information log). If shader has no information log, a value of 0 is returned.
Gl.SHADER_SOURCE_LENGTH: params returns the length of the concatenation of the source strings that make up the shader source for the shader, including the null termination character. (i.e., the size of the character buffer required to store the shader source). If no source code exists, 0 is returned.

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

Gl.INVALID_VALUE is generated if shader is not a value generated by OpenGL.

Gl.INVALID_OPERATION is generated if shader does not refer to a shader object.

Gl.INVALID_ENUM is generated if pname is not an accepted value.

Gl.GetShaderInfoLog with argument shader

Gl.GetShaderSource with argument shader

Gl.GetShaderiv (gb.opengl.glsl)