FRONTPANEL: Add OS X support to sim_frontpanel, add build requirements to documentation.

sim_frontpanel.c

@@ -68,12 +68,44 @@ tp->tv_sec = (long)(now/10000000);
 tp->tv_nsec = (now%10000000)*100;
 return 0;
 }
-#else
+#else /* NOT _WIN32 */
 #include <unistd.h>
 #define msleep(n) usleep(1000*n)
 #include <sys/wait.h>
+#if defined (__APPLE__)
+#define HAVE_STRUCT_TIMESPEC 1   /* OSX defined the structure but doesn't tell us */
 #endif
 
+/* on HP-UX, CLOCK_REALTIME is enum, not preprocessor define */
+#if !defined(CLOCK_REALTIME) && !defined(__hpux)
+#define CLOCK_REALTIME 1
+#define NEED_CLOCK_GETTIME 1
+#if !defined(HAVE_STRUCT_TIMESPEC)
+#define HAVE_STRUCT_TIMESPEC 1
+#if !defined(_TIMESPEC_DEFINED)
+#define _TIMESPEC_DEFINED
+struct timespec {
+    long   tv_sec;
+    long   tv_nsec;
+};
+#endif /* _TIMESPEC_DEFINED */
+#endif /* HAVE_STRUCT_TIMESPEC */
+#if defined(NEED_CLOCK_GETTIME)
+int clock_gettime(int clk_id, struct timespec *tp)
+{
+struct timeval cur;
+struct timezone foo;
+
+gettimeofday (&cur, &foo);
+tp->tv_sec = cur.tv_sec;
+tp->tv_nsec = cur.tv_usec*1000;
+return 0;
+}
+#endif /* defined(NEED_CLOCK_GETTIME) */
+#endif /* !defined(CLOCK_REALTIME) && !defined(__hpux) */
+
+#endif /* NOT _WIN32 */
+
 typedef struct {
     char *name;
     void *addr;

sim_frontpanel.h

@@ -29,6 +29,15 @@
    simulator.  Facilities provide ways to gather information from and to 
    observe and control the state of a simulator.
 
+   Any application which wants to use this API needs to:
+      1) include this file in the application code
+      2) compile sim_frontpanel.c and sim_sock.c from the top level directory 
+         of the simh source.
+      3) link the sim_frontpanel and sim_sock object modules and libpthreads 
+         into the application.
+      4) Use a simh simulator built from the same version of simh that the
+         sim_frontpanel and sim_sock modules came from.
+
 */
 
 #ifndef SIM_FRONTPANEL_H_