/****************************************************************************
- * Copyright (c) 1998-2007,2009 Free Software Foundation, Inc. *
+ * Copyright (c) 1998-2011,2012 Free Software Foundation, Inc. *
* *
* Permission is hereby granted, free of charge, to any person obtaining a *
* copy of this software and associated documentation files (the *
#include <curses.priv.h>
-MODULE_ID("$Id: setbuf.c,v 1.15 2009/05/23 22:13:44 tom Exp $")
+MODULE_ID("$Id: setbuf.c,v 1.19 2012/08/25 20:48:05 tom Exp $")
/*
- * If the output file descriptor is connected to a tty (the typical case) it
- * will probably be line-buffered. Keith Bostic pointed out that we don't want
- * this; it hoses people running over networks by forcing out a bunch of small
- * packets instead of one big one, so screen updates on ptys look jerky.
- * Restore block buffering to prevent this minor lossage.
- *
- * The buffer size is a compromise. Ideally we'd like a buffer that can hold
- * the maximum possible update size (the whole screen plus cup commands to
- * change lines as it's painted). On a 66-line xterm this can become
- * excessive. So we min it with the amount of data we think we can get through
- * two Ethernet packets (maximum packet size - 100 for TCP/IP overhead).
- *
- * Why two ethernet packets? It used to be one, on the theory that said
- * packets define the maximum size of atomic update. But that's less than the
- * 2000 chars on a 25 x 80 screen, and we don't want local updates to flicker
- * either. Two packet lengths will handle up to a 35 x 80 screen.
- *
- * The magic '6' is the estimated length of the end-of-line cup sequence to go
- * to the next line. It's generous. We used to mess with the buffering in
- * init_mvcur() after cost computation, but that lost the sequences emitted by
- * init_acs() in setupscreen().
- *
- * "The setvbuf function may be used only after the stream pointed to by stream
- * has been associated with an open file and before any other operation is
- * performed on the stream." (ISO 7.9.5.6.)
- *
- * Grrrr...
- *
- * On a lighter note, many implementations do in fact allow an application to
- * reset the buffering after it has been written to. We try to do this because
- * otherwise we leave stdout in buffered mode after endwin() is called. (This
- * also happens with SVr4 curses).
- *
- * There are pros/cons:
- *
- * con:
- * There is no guarantee that we can reestablish buffering once we've
- * dropped it.
- *
- * We _may_ lose data if the implementation does not coordinate this with
- * fflush.
- *
- * pro:
- * An implementation is more likely to refuse to change the buffering than
- * to do it in one of the ways mentioned above.
- *
- * The alternative is to have the application try to change buffering
- * itself, which is certainly no improvement.
- *
- * Just in case it does not work well on a particular system, the calls to
- * change buffering are all via the macro NC_BUFFERED. Some implementations
- * do indeed get confused by changing setbuf on/off, and will overrun the
- * buffer. So we disable this by default (there may yet be a workaround).
+ * Obsolete entrypoint retained for binary compatbility.
*/
NCURSES_EXPORT(void)
-NCURSES_SP_NAME(_nc_set_buffer) (NCURSES_SP_DCLx FILE *ofp, bool buffered)
+NCURSES_SP_NAME(_nc_set_buffer) (NCURSES_SP_DCLx FILE *ofp, int buffered)
{
- int Cols;
- int Lines;
-
- if (0 == SP_PARM)
- return;
-
- Cols = *(ptrCols(SP_PARM));
- Lines = *(ptrLines(SP_PARM));
-
- /* optional optimization hack -- do before any output to ofp */
-#if HAVE_SETVBUF || HAVE_SETBUFFER
- if (SP_PARM->_buffered != buffered) {
- unsigned buf_len;
- char *buf_ptr;
-
- if (getenv("NCURSES_NO_SETBUF") != 0)
- return;
-
- fflush(ofp);
-#ifdef __DJGPP__
- setmode(ofp, O_BINARY);
-#endif
- if (buffered != 0) {
- buf_len = min(Lines * (Cols + 6), 2800);
- if ((buf_ptr = SP_PARM->_setbuf) == 0) {
- if ((buf_ptr = typeMalloc(char, buf_len)) == NULL)
- return;
- SP_PARM->_setbuf = buf_ptr;
- /* Don't try to free this! */
- }
-#if !USE_SETBUF_0
- else
- return;
-#endif
- } else {
-#if !USE_SETBUF_0
- return;
-#else
- buf_len = 0;
- buf_ptr = 0;
-#endif
- }
-
-#if HAVE_SETVBUF
-#ifdef SETVBUF_REVERSED /* pre-svr3? */
- (void) setvbuf(ofp, buf_ptr, buf_len, buf_len ? _IOFBF : _IOLBF);
-#else
- (void) setvbuf(ofp, buf_ptr, buf_len ? _IOFBF : _IOLBF, buf_len);
-#endif
-#elif HAVE_SETBUFFER
- (void) setbuffer(ofp, buf_ptr, (int) buf_len);
+#if NCURSES_SP_FUNCS
+ (void) SP_PARM;
#endif
-
- SP_PARM->_buffered = buffered;
- }
-#endif /* HAVE_SETVBUF || HAVE_SETBUFFER */
+ (void) ofp;
+ (void) buffered;
}
#if NCURSES_SP_FUNCS
NCURSES_EXPORT(void)
-_nc_set_buffer(FILE *ofp, bool buffered)
+_nc_set_buffer(FILE *ofp, int buffered)
{
NCURSES_SP_NAME(_nc_set_buffer) (CURRENT_SCREEN, ofp, buffered);
}
projects / ncurses.git / blobdiff