Specifies the symbolic name of a map. Accepted values are GL_MAP1_COLOR_4, GL_MAP1_INDEX, GL_MAP1_NORMAL, GL_MAP1_TEXTURE_COORD_1, GL_MAP1_TEXTURE_COORD_2, GL_MAP1_TEXTURE_COORD_3, GL_MAP1_TEXTURE_COORD_4, GL_MAP1_VERTEX_3, GL_MAP1_VERTEX_4, GL_MAP2_COLOR_4, GL_MAP2_INDEX, GL_MAP2_NORMAL, GL_MAP2_TEXTURE_COORD_1, GL_MAP2_TEXTURE_COORD_2, GL_MAP2_TEXTURE_COORD_3, GL_MAP2_TEXTURE_COORD_4, GL_MAP2_VERTEX_3, and GL_MAP2_VERTEX_4.

Specifies which parameter to return. Symbolic names GL_COEFF, GL_ORDER, and GL_DOMAIN are accepted.

Returns the requested data.

v returns the control points for the evaluator function. One-dimensional evaluators return $\mathit{order}$ control points, and two-dimensional evaluators return $\mathit{uorder}\times \mathit{vorder}$ control points. Each control point consists of one, two, three, or four integer, single-precision floating-point, or double-precision floating-point values, depending on the type of the evaluator. The GL returns two-dimensional control points in row-major order, incrementing the $\mathit{uorder}$ index quickly and the $\mathit{vorder}$ index after each row. Integer values, when requested, are computed by rounding the internal floating-point values to the nearest integer values.

v returns the order of the evaluator function. One-dimensional evaluators return a single value, $\mathit{order}$. The initial value is 1. Two-dimensional evaluators return two values, $\mathit{uorder}$ and $\mathit{vorder}$. The initial value is 1,1.

v returns the linear $\mathit{u}$ and $\mathit{v}$ mapping parameters. One-dimensional evaluators return two values, $\mathit{u1}$ and $\mathit{u2}$, as specified by glMap1. Two-dimensional evaluators return four values ($\mathit{u1}$, $\mathit{u2}$, $\mathit{v1}$, and $\mathit{v2}$) as specified by glMap2. Integer values, when requested, are computed by rounding the internal floating-point values to the nearest integer values.