From 5046dbb4a7eba5eccfd258f92f4735c9ffc8d069 Mon Sep 17 00:00:00 2001 From: Zack Weinberg Date: Thu, 8 Jun 2017 15:39:03 -0400 Subject: Prepare for radical source tree reorganization. All top-level files and directories are moved into a temporary storage directory, REORG.TODO, except for files that will certainly still exist in their current form at top level when we're done (COPYING, COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which are moved to the new directory OldChangeLogs, instead), and the generated file INSTALL (which is just deleted; in the new order, there will be no generated files checked into version control). --- manual/examples/swapcontext.c | 116 ------------------------------------------ 1 file changed, 116 deletions(-) delete mode 100644 manual/examples/swapcontext.c (limited to 'manual/examples/swapcontext.c') diff --git a/manual/examples/swapcontext.c b/manual/examples/swapcontext.c deleted file mode 100644 index 3747230c31..0000000000 --- a/manual/examples/swapcontext.c +++ /dev/null @@ -1,116 +0,0 @@ -/* Complete Context Control - Copyright (C) 1991-2017 Free Software Foundation, Inc. - - This program is free software; you can redistribute it and/or - modify it under the terms of the GNU General Public License - as published by the Free Software Foundation; either version 2 - of the License, or (at your option) any later version. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU General Public License for more details. - - You should have received a copy of the GNU General Public License - along with this program; if not, if not, see . -*/ - -#include -#include -#include -#include -#include - -/* Set by the signal handler. */ -static volatile int expired; - -/* The contexts. */ -static ucontext_t uc[3]; - -/* We do only a certain number of switches. */ -static int switches; - - -/* This is the function doing the work. It is just a - skeleton, real code has to be filled in. */ -static void -f (int n) -{ - int m = 0; - while (1) - { - /* This is where the work would be done. */ - if (++m % 100 == 0) - { - putchar ('.'); - fflush (stdout); - } - - /* Regularly the @var{expire} variable must be checked. */ - if (expired) - { - /* We do not want the program to run forever. */ - if (++switches == 20) - return; - - printf ("\nswitching from %d to %d\n", n, 3 - n); - expired = 0; - /* Switch to the other context, saving the current one. */ - swapcontext (&uc[n], &uc[3 - n]); - } - } -} - -/* This is the signal handler which simply set the variable. */ -void -handler (int signal) -{ - expired = 1; -} - - -int -main (void) -{ - struct sigaction sa; - struct itimerval it; - char st1[8192]; - char st2[8192]; - - /* Initialize the data structures for the interval timer. */ - sa.sa_flags = SA_RESTART; - sigfillset (&sa.sa_mask); - sa.sa_handler = handler; - it.it_interval.tv_sec = 0; - it.it_interval.tv_usec = 1; - it.it_value = it.it_interval; - - /* Install the timer and get the context we can manipulate. */ - if (sigaction (SIGPROF, &sa, NULL) < 0 - || setitimer (ITIMER_PROF, &it, NULL) < 0 - || getcontext (&uc[1]) == -1 - || getcontext (&uc[2]) == -1) - abort (); - - /* Create a context with a separate stack which causes the - function @code{f} to be call with the parameter @code{1}. - Note that the @code{uc_link} points to the main context - which will cause the program to terminate once the function - return. */ - uc[1].uc_link = &uc[0]; - uc[1].uc_stack.ss_sp = st1; - uc[1].uc_stack.ss_size = sizeof st1; - makecontext (&uc[1], (void (*) (void)) f, 1, 1); - - /* Similarly, but @code{2} is passed as the parameter to @code{f}. */ - uc[2].uc_link = &uc[0]; - uc[2].uc_stack.ss_sp = st2; - uc[2].uc_stack.ss_size = sizeof st2; - makecontext (&uc[2], (void (*) (void)) f, 1, 2); - - /* Start running. */ - swapcontext (&uc[0], &uc[1]); - putchar ('\n'); - - return 0; -} -- cgit v1.2.3-70-g09d2