glGetProgramResourceIndex

glGetProgramResourceIndex: man4/glGetProgramResourceIndex.xml

glGetProgramResourceIndex returns the unsigned integer index assigned to a resource named name in the interface type programInterface of program object program. program must be the name of an existing program object. programInterface is the name of the interface within program which contains the resource named name and must be one of the following values: If name exactly matches the name string of one of the active resources for programInterface, the index of the matched resource is returned. Additionally, if name would exactly match the name string of an active resource if "[0]" were appended to name, the index of the matched resource is returned. Otherwise, name is considered not to be the name of an active resource, and GL_INVALID_INDEX is returned. For the interface GL_TRANSFORM_FEEDBACK_VARYING, the value GL_INVALID_INDEX should be returned when querying the index assigned to the special names gl_NextBuffer, gl_SkipComponents1, gl_SkipComponents2, gl_SkipComponents3, or gl_SkipComponents4.