Preliminary signal handling.

[pdclib] / platform / example_cygwin / internals / _PDCLIB_config.h

diff --git a/platform/example_cygwin/internals/_PDCLIB_config.h b/platform/example_cygwin/internals/_PDCLIB_config.h
index 2fd09e9706becf513c23796fe4748d5c071eb4f8..8512ad9295d7b85976756fe330c8cacd868fec92 100644 (file)
--- a/platform/example_cygwin/internals/_PDCLIB_config.h
+++ b/platform/example_cygwin/internals/_PDCLIB_config.h
@@ -287,3 +287,39 @@ typedef int _PDCLIB_fd_t;
 #define _PDCLIB_UNGETCBUFSIZE 1
 
 typedef long wint_t;
+
+/* Signals ------------------------------------------------------------------ */
+
+/* A word on signals, to the people using PDCLib in their OS projects.
+
+   The way they are defined by the C standard severely limits their usefulness,
+   to the point where a library implementation need not interface with the OS'
+   signals at all (which is what the PDCLib example implementation does).
+   (Other issues include, for example, that signal handlers are not re-entrant.)
+
+   Thus, it is strongly discouraged to try bolting on a signal handling infra-
+   structure onto <signal.h>. Since C's signal handling is so limited to begin
+   with, and code using it is pretty much non-portable anyway, it would be
+   smarter to keep <signal.h> in the barely functional state it is in, and
+   instead create a better, OS-specific API.
+
+   That being said, the below signals require to be defined to a positive int
+   value. I took what my Linux box defined them to; if you have to change them,
+   and what value to change them *to*, depends heavily on your environment and
+   what you are expecting <signal.h> to accomplish (see above).
+*/
+#define _PDCLIB_SIGABRT 6
+#define _PDCLIB_SIGFPE  8
+#define _PDCLIB_SIGILL  4
+#define _PDCLIB_SIGINT  2
+#define _PDCLIB_SIGSEGV 11
+#define _PDCLIB_SIGTERM 15
+
+/* The following should be defined to pointer values that could NEVER point to
+   a valid function. (They are used as special arguments to signal().) Again, I
+   took the values of my Linux box, which should be as good as any other value.
+*/
+#define _PDCLIB_SIG_DFL (void (*)( int ))0
+#define _PDCLIB_SIG_ERR (void (*)( int ))-1
+#define _PDCLIB_SIG_IGN (void (*)( int ))1
+