RJK's general signal-handling robustness patch. Should fix the weird

spin behaviour occasionally seen after pterm's child process dies.

[originally from svn r2181]

unix/signal.c

@@ -0,0 +1,31 @@
+#include <signal.h>
+
+/*
+ * Calling signal() is a non-portable, as it varies in meaning between
+ * platforms and depending on feature macros, and has stupid semantics
+ * at least some of the time.
+ *
+ * This function provides the same interface as the libc function, but
+ * provides consistent semantics.  It assumes POSIX semantics for
+ * sigaction() (so you might need to do some more work if you port to
+ * something ancient like SunOS 4)
+ */
+void (*putty_signal(int sig, void (*func)(int)))(int) {
+    struct sigaction sa;
+    struct sigaction old;
+    
+    sa.sa_handler = func;
+    if(sigemptyset(&sa.sa_mask) < 0)
+	return SIG_ERR;
+    sa.sa_flags = SA_RESTART;
+    if(sigaction(sig, &sa, &old) < 0)
+	return SIG_ERR;
+    return old.sa_handler;
+}
+
+/*
+Local Variables:
+c-basic-offset:4
+comment-column:40
+End:
+*/