GLFLUSH() MachTen Programmer’s Manual GLFLUSH()

NAME
glFlush - force execution of GL commands in finite time

C SPECIFICATION
void glFlush( void )

DESCRIPTION
Different GL implementations buffer commands in several
different locations, including network buffers and the
graphics accelerator itself. glFlush empties all of these
buffers, causing all issued commands to be executed as
quickly as they are accepted by the actual rendering
engine. Though this execution may not be completed in any
particular time period, it does complete in finite time.

Because any GL program might be executed over a network,
or on an accelerator that buffers commands, all programs
should call glFlush whenever they count on having all of
their previously issued commands completed. For example,
call glFlush before waiting for user input that depends on
the generated image.

NOTES
glFlush can return at any time. It does not wait until
the execution of all previously issued GL commands is com-
plete.

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