-#ifdef __SOLARIS__
-// somehow missing from sys/wait.h but in the system's docs
-extern "C"
-{
- pid_t wait4(pid_t pid, int *statusp, int options, struct rusage
- *rusage);
-}
-#endif
+// many versions of Unices have this function, but it is not defined in system
+// headers - please add your system here if it is the case for your OS.
+// SunOS (and Solaris) and DG-UX are like this.
+#if defined(__SOLARIS__) || defined(__osf__)
+ extern "C"
+ {
+ pid_t wait4(pid_t pid, int *statusp, int options,
+ struct rusage *rusage);
+ }
+
+ #define wxWait4(pid, stat, flags, rusage) wait4(pid, stat, flags, rusage)
+#elif defined(__sgi) || defined(__HPUX__)
+ // no wait4() at all on these systems
+ // TODO verify whether wait3() really works in this situation
+ #define wxWait4(pid, stat, flags, rusage) wait3(stat, flags, rusage)
+#else
+ // other Unices: assume have wait4(), although it's not standard (but
+ // Linux and FreeBSD do have it)
+ #define wxWait4(pid, stat, flags, rusage) wait4(pid, stat, flags, rusage)
+#endif // wait4()