• Tor Lillqvist's avatar
    Finally, a new and improved IO Channel and condition watch implementation · b965bb5d
    Tor Lillqvist authored
    2000-07-30  Tor Lillqvist  <tml@iki.fi>
    
    	Finally, a new and improved IO Channel and condition watch
    	implementation for Win32. Based on code provided by Craig Setera.
    
    	When watching file descriptors, for which there is no select()
    	like functionality on Win32 that would work on all Win32 platforms
    	for all types of file descriptors (including anonymous pipes), we
    	start a new thread that blocks while trying to read from the file
    	descriptor. When the read returns, a Win32 Event is signalled that
    	the polling routine eventually notices. Meanwhile, the data being
    	read is stored in a circular buffer, from where the IO channel's
    	read() method picks it up.
    
    	If the buffer fills up the reading thread has to wait for space
    	becoming available. For this another Win32 Event is used. The IO
    	Channel's read() method signals this when it has read some data
    	out of the buffer.
    
    	The separate reader thread(s), and the circular buffer(s) with
    	associated events mean lots of possibilities for fun parallellism
    	errors. But it seems to work OK, i.e. GIMP runs.
    
    	* gmain.c: Small changes to the Win32 polling function.
    	(g_main_win32_get_poll_func): New function. Perhaps it would be a
    	good idea to provide this on all platforms.
    
    	* giowin32.c: The bulk of the new implementation.
    	(g_io_channel_win32_wait_for_condition): New function. To be used
    	where on Unix one does a select() on the channel's fd, like
    	libgimp's gimp_extension_process(). Could be provided on all
    	platforms.
    
    	* glib.h: Update documentation for IO Channels on Win32. Remove
    	the declarations for the as of now obsolete old functions related
    	to IO Channels for pipes with "wakeup" messages.
    
    	* glib.def: Some new functions.
    
    	* tests/gio-test.c: New file, to test GIOChannel and main loop.
    
    	* tests/Makefile.am
    	* tests/makefile.mingw.in: Add it.
    b965bb5d
glib.h 109 KB