OpenGL函数解析-glGetString

glGetString

NAME

glGetString -- returns a string describing
the current GL connection

C SPECIFICATION

const GLubyte *glGetString(GLenum name)

PARAMETERS

nameSpecifies a symbolic constant, one of GL_VENDOR, GL_RENDERER, GL_VERSION, orGL_EXTENSIONS.

DESCRIPTION

glGetString returns a pointer to a static
string describing some aspect of the current GL connection. name can
be one of the following:
GL_VENDORReturns the company responsible for this GL implementation. This name does not change from release to release.

GL_RENDERERReturns the name of the renderer. This name is typically specific to a particular configuration of a hardware platform. It does not change from release to release.

GL_VERSIONReturns a version or release number.

GL_EXTENSIONSReturns a space-separated list of supported extensions to GL.

Because GL does not include queries for the performance characteristics of an implementation, it is expected that some applications will be written to recognize
known platforms and will modify their GL usage based on known performance characteristics of these platforms. Strings GL_VENDOR and GL_RENDERER together
uniquely specify a platform, and will not change from release to release. They should be used by such platform recognition algorithms. The format and contents of the GL_VENDOR and
the GL_RENDERER strings depend on
the implementation.

Some applications will want to make use of features which are not part of the standard GL. These features are may be implemented as extensions to the standard GL. The GL_EXTENSIONS string is a space seperated list of supported GL extensions.
(Extension names never contain a space character.)

The GL_VERSION string begins with a version number. The version number is of the formmajor_number.minor_number or major_number.minor_number.release_number. Vendor specific information may follow
the version number. It's format depends on the implementation, but a space always seperates the version number and the vendor specific information.

All strings are null-terminated.

NOTES

If an error is generated, glGetString returns
zero.

The client and server may support different versions or extensions. glGetString always returns a compatible version number or list of extensions. The release number always describes the server.

ERRORS

GL_INVALID_ENUM is generated if name is
not an accepted value.

GL_INVALID_OPERATION is generated if glGetString is called between a call to glBegin and
the corresponding call to glEnd.