glGetBooleanv

glGetBooleanv is an OpenGL API function used to query the current boolean-valued state of the rendering context. It retrieves the value of a specified pname and returns it as one or more GLboolean values stored in the provided data buffer. The function is available in both compatibility and core profiles of OpenGL.

Prototype and parameters: void glGetBooleanv(GLenum pname, GLboolean *data). The pname parameter selects the state variable to query. The data parameter points to a buffer where the resulting boolean value(s) will be stored. For single-valued booleans, data must point to a single GLboolean. For multi-component booleans (for example, GL_COLOR_WRITEMASK, which returns four booleans), data must point to an array with the appropriate length (typically four elements).

Behavior and usage: glGetBooleanv returns the current value of the specified state as a GLboolean. Values are interpreted such that zero maps to GL_FALSE and non-zero maps to GL_TRUE. Common uses include querying whether a capability is enabled (e.g., GL_DEPTH_TEST) or obtaining the components of a boolean mask (e.g., GL_COLOR_WRITEMASK). Example usage includes glGetBooleanv(GL_DEPTH_TEST, &enabled) or glGetBooleanv(GL_COLOR_WRITEMASK, mask) with a four-element boolean array.

Error handling and notes: If pname does not correspond to a supported boolean-valued parameter, GL_INVALID_ENUM is generated. As with other glGet* calls, data must point to a valid writable buffer of sufficient length for the requested parameter. glGetBooleanv is typically paired with glGetIntegerv or glGetFloatv when differing data representations are needed.