glIsEnabled returns GL_TRUE if cap is an enabled capability and returns GL_FALSE otherwise. Initially all capabilities except GL_DITHER are disabled; GL_DITHER is initially enabled.
The following capabilities are accepted for cap:
| Constant | See |
| GL_ALPHA_TEST | glAlphaFunc |
| GL_AUTO_NORMAL | glEvalCoord |
| GL_BLEND | glBlendFunc , glLogicOp |
| GL_CLIP_PLANEi | glClipPlane |
| GL_COLOR_ARRAY | glColorPointer |
| GL_COLOR_LOGIC_OP | glLogicOp |
| GL_COLOR_MATERIAL | glColorMaterial |
| GL_COLOR_TABLE | glColorTable |
| GL_CONVOLUTION_1D | glConvolutionFilter1D |
| GL_CONVOLUTION_2D | glConvolutionFilter2D |
| GL_CULL_FACE | glCullFace |
| GL_DEPTH_TEST | glDepthFunc , glDepthRange |
| GL_DITHER | glEnable |
| GL_EDGE_FLAG_ARRAY | glEdgeFlagPointer |
| GL_FOG | glFog |
| GL_HISTOGRAM | glHistogram |
| GL_INDEX_ARRAY | glIndexPointer |
| GL_INDEX_LOGIC_OP | glLogicOp |
| GL_LIGHTi | glLightModel , glLight |
| GL_LIGHTING | glMaterial , glLightModel , glLight |
| GL_LINE_SMOOTH | glLineWidth |
| GL_LINE_STIPPLE | glLineStipple |
| GL_MAP1_COLOR_4 | glMap1 |
| GL_MAP1_INDEX | glMap1 |
| GL_MAP1_NORMAL | glMap1 |
| GL_MAP1_TEXTURE_COORD_1 | glMap1 |
| GL_MAP1_TEXTURE_COORD_2 | glMap1 |
| GL_MAP1_TEXTURE_COORD_3 | glMap1 |
| GL_MAP1_TEXTURE_COORD_4 | glMap1 |
| GL_MAP2_COLOR_4 | glMap2 |
| GL_MAP2_INDEX | glMap2 |
| GL_MAP2_NORMAL | glMap2 |
| GL_MAP2_TEXTURE_COORD_1 | glMap2 |
| GL_MAP2_TEXTURE_COORD_2 | glMap2 |
| GL_MAP2_TEXTURE_COORD_3 | glMap2 |
| GL_MAP2_TEXTURE_COORD_4 | glMap2 |
| GL_MAP2_VERTEX_3 | glMap2 |
| GL_MAP2_VERTEX_4 | glMap2 |
| GL_MINMAX | glMinmax |
| GL_NORMAL_ARRAY | glNormalPointer |
| GL_NORMALIZE | glNormal |
| GL_POINT_SMOOTH | glPointSize |
| GL_POLYGON_SMOOTH | glPolygonMode |
| GL_POLYGON_OFFSET_FILL | glPolygonOffset |
| GL_POLYGON_OFFSET_LINE | glPolygonOffset |
| GL_POLYGON_OFFSET_POINT | glPolygonOffset |
| GL_POLYGON_STIPPLE | glPolygonStipple |
| GL_POST_COLOR_MATRIX_COLOR_TABLE | glColorTable |
| GL_POST_CONVOLUTION_COLOR_TABLE | glColorTable |
| GL_RESCALE_NORMAL | glNormal |
| GL_SCISSOR_TEST | glScissor |
| GL_SEPARABLE_2D | glSeparableFilter2D |
| GL_STENCIL_TEST | glStencilFunc , glStencilOp |
| GL_TEXTURE_1D | glTexImage1D |
| GL_TEXTURE_2D | glTexImage2D |
| GL_TEXTURE_3D | glTexImage3D |
| GL_TEXTURE_COORD_ARRAY | glTexCoordPointer |
| GL_TEXTURE_GEN_Q | glTexGen |
| GL_TEXTURE_GEN_R | glTexGen |
| GL_TEXTURE_GEN_S | glTexGen |
| GL_TEXTURE_GEN_T | glTexGen |
| GL_VERTEX_ARRAY | glVertexPointer |
If an error is generated, glIsEnabled returns 0.
GL_COLOR_LOGIC_OP, GL_COLOR_ARRAY, GL_EDGE_FLAG_ARRAY, GL_INDEX_ARRAY, GL_INDEX_LOGIC_OP, GL_NORMAL_ARRAY, GL_POLYGON_OFFSET_FILL, GL_POLYGON_OFFSET_LINE, GL_POLYGON_OFFSET_POINT, GL_TEXTURE_COORD_ARRAY, and GL_VERTEX_ARRAY are available only if the GL version is 1.1 or greater
GL_RESCALE_NORMAL, and GL_TEXTURE_3D are available only if the GL version is 1.2 or greater.
GL_COLOR_TABLE, GL_CONVOLUTION_1D, GL_CONVOLUTION_2D, GL_HISTOGRAM, GL_MINMAX, GL_POST_COLOR_MATRIX_COLOR_TABLE, GL_POST_CONVOLUTION_COLOR_TABLE, and GL_SEPARABLE_2D are available only if GL_ARB_imaging is returned when glGet is called with GL_EXTENSIONS.
When the GL_ARB_multitexture extension is supported, the following parameters return the associated value for the active texture unit. GL_TEXTURE_1D, GL_TEXTURE_BINDING_1D, GL_TEXTURE_2D, GL_TEXTURE_BINDING_2D, GL_TEXTURE_3D, GL_TEXTURE_BINDING_3D, GL_TEXTURE_GEN_S, GL_TEXTURE_GEN_T, GL_TEXTURE_GEN_R, GL_TEXTURE_GEN_Q, GL_TEXTURE_MATRIX, and GL_TEXTURE_STACK_DEPTH. Likewise, the following parameters return the associated value for the active client texture unit: GL_TEXTURE_COORD_ARRAY, GL_TEXTURE_COORD_ARRAY_SIZE, GL_TEXTURE_COORD_ARRAY_STRIDE, GL_TEXTURE_COORD_ARRAY_TYPE.