glFinishAsyncSGIX(3G)

NAME
     glFinishAsyncSGIX - wait for completion of an asynchronous command


C SPECIFICATION
     GLint glFinishAsyncSGIX( GLuint *markerp )


PARAMETERS
     markerp  Returns a marker for a completed asynchronous command.

DESCRIPTION
     glFinishAsyncSGIX 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.

     glFinishAsyncSGIX returns 1 when an asynchronous command has completed;
     in this case it writes the marker associated with the completed command
     into the integer referred to by markerp.  If there are pending
     asynchronous commands but none have completed, glFinishAsyncSGIX blocks
     waiting for one.  If there are no pending asynchronous commands,
     glFinishAsyncSGIX returns 0 immediately and does not modify the integer
     referred to by markerp.

     Once OpenGL has reported the completion of an asynchronous command via
     either glFinishAsyncSGIX or glPollAsyncSGIX, the completion status of the
     command will not be reported again.  If several commands have the same
     marker associated with them, the completion status of each command will
     be reported separately, although these reports will be indistinguishable.
     The order in which asynchronous commands are reported is undefined.
     A program may guarantee that all outstanding asynchronous commands have
     completed by calling glFinish.  A call to glFinish does not cause the
     completion status of outstanding commands to be reported, so subsequent
     calls to glFinishAsyncSGIX or glPollAsyncSGIX will report the status of
     such commands.

ERRORS
     GL_INVALID_OPERATION is generated if glFinishAsyncSGIX 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
     glAsyncMarkerSGIX, glDeleteAsyncMarkersSGIX, glGenAsyncMarkersSGIX,
     glIsAsyncMarkerSGIX, glPollAsyncSGIX, glDrawPixels, glGet, glReadPixels,
     glTexImage1D, glTexImage2D, glTexImage3D, glTexSubImage1D,
     glTexSubImage2D, glTexSubImage3D