glAsyncMarkerSGIX(3G)	       OpenGL Reference		 glAsyncMarkerSGIX(3G)

NAME    [Toc]    [Back]

     glAsyncMarkerSGIX - set a marker for tracking asynchronous	commands

C SPECIFICATION    [Toc]    [Back]

     void glAsyncMarkerSGIX( GLuint marker )

PARAMETERS    [Toc]    [Back]

     marker  Specifies a marker	value for tracking asynchronous	commands.

DESCRIPTION    [Toc]    [Back]

     glAsyncMarkerSGIX is part of the SGIX_async extension.  This extension
     provides a	framework within which particular sets of OpenGL commands can
     become "asynchronous" via specific	further	OpenGL extensions.  Currently
     the SGIX_async_pixel extension is the only	such defined extension.

     Asynchronous commands are commands	that may complete out-of-order with
     respect to	other OpenGL commands.	An asynchronous	command	samples	the
     OpenGL state vector when it is issued.  The sampled state includes	the
     results from the complete execution of all	synchronous (normal) commands
     issued prior to the asynchronous command.	However, the results of	an
     asynchronous command (state changes or framebuffer	updates) are not
     necessarily committed in order.  An asynchronous command may commit its
     results any time after the	completion of all synchronous commands issued
     prior to the asynchronous command.	 An implementation may choose to
     execute asynchronous commands in parallel with subsequent commands	or at
     some convenient time in the future.

     Implementations of	asynchronous commands may also be non-blocking.	 For
     example, a	non-blocking query command returns control to the program
     immediately rather	than stalling the program until	the results of the
     query are available.

     Note that this language allows any	particular asynchronous	command	to
     behave exactly as if it were not asynchronous, if the implementation
     chooses.

     glAsyncMarkerSGIX sets the	value of GL_ASYNC_MARKER_SGIX.	When an
     asynchronous command is issued, the current value of GL_ASYNC_MARKER_SGIX
     is	associated with	the particular invocation of the command.  This	value
     is	an integer called a "marker" which can be used by the application to
     identify a	particular command when	it completes.  It is not an error to
     invoke multiple asynchronous commands without changing
     GL_ASYNC_MARKER_SGIX, although such a situation may make it impossible
     for the application to distinguish	the completion status of the commands.

     Note that the marker name space is	never shared across contexts, as the
     name spaces for texture objects and display lists may be.






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glAsyncMarkerSGIX(3G)	       OpenGL Reference		 glAsyncMarkerSGIX(3G)



     The initial value for GL_ASYNC_MARKER_SGIX	is 0.

ERRORS    [Toc]    [Back]

     GL_INVALID_OPERATION is generated if glAsyncMarkerSGIX is executed
     between the execution of glBegin and the corresponding execution of
     glEnd.


MACHINE	DEPENDENCIES
     The SGIX_async and	SGIX_async_pixel extensions are	implemented only on
     Octane2 VPro systems.

SEE ALSO    [Toc]    [Back]

     glDeleteAsyncMarkersSGIX, glFinishAsyncSGIX, glGenAsyncMarkersSGIX,
     glIsAsyncMarkerSGIX, glPollAsyncSGIX, glDrawPixels, glGet,	glReadPixels,
     glTexImage1D, glTexImage2D, glTexImage3D, glTexSubImage1D,
     glTexSubImage2D, glTexSubImage3D


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