Prepare for radical source tree reorganization.zack/build-layout-experiment

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).

1 files changed, 78 insertions, 0 deletions

diff --git a/REORG.TODO/manual/examples/sigusr.c b/REORG.TODO/manual/examples/sigusr.c
new file mode 100644
index 0000000000..51b44dcf03
--- /dev/null
+++ b/REORG.TODO/manual/examples/sigusr.c
@@ -0,0 +1,78 @@
+/* Using kill for Communication
+   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 <http://www.gnu.org/licenses/>.
+*/
+
+/*@group*/
+#include <signal.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <unistd.h>
+/*@end group*/
+
+/* When a @code{SIGUSR1} signal arrives, set this variable.  */
+volatile sig_atomic_t usr_interrupt = 0;
+
+void
+synch_signal (int sig)
+{
+  usr_interrupt = 1;
+}
+
+/* The child process executes this function. */
+void
+child_function (void)
+{
+  /* Perform initialization. */
+  printf ("I'm here!!!  My pid is %d.\n", (int) getpid ());
+
+  /* Let parent know you're done. */
+  kill (getppid (), SIGUSR1);
+
+  /* Continue with execution. */
+  puts ("Bye, now....");
+  exit (0);
+}
+
+int
+main (void)
+{
+  struct sigaction usr_action;
+  sigset_t block_mask;
+  pid_t child_id;
+
+  /* Establish the signal handler. */
+  sigfillset (&block_mask);
+  usr_action.sa_handler = synch_signal;
+  usr_action.sa_mask = block_mask;
+  usr_action.sa_flags = 0;
+  sigaction (SIGUSR1, &usr_action, NULL);
+
+  /* Create the child process. */
+  child_id = fork ();
+  if (child_id == 0)
+    child_function ();		/* Does not return.  */
+
+/*@group*/
+  /* Busy wait for the child to send a signal. */
+  while (!usr_interrupt)
+    ;
+/*@end group*/
+
+  /* Now continue execution. */
+  puts ("That's all, folks!");
+
+  return 0;
+}