detect windows cpus

configure.ac

@@ -68,7 +68,8 @@ AC_SYS_LARGEFILE
 AC_FUNC_MALLOC
 AC_FUNC_REALLOC
 AC_FUNC_STRTOD
-AC_CHECK_FUNCS([memchr memmove memset strerror strtol sched_getaffinity])
+AC_CHECK_FUNCS([memchr memmove memset strerror strtol sched_getaffinity sysconf
+  GetSystemInfo])
 AC_CHECK_HEADER([sys/endian.h],
                [
                  AC_CHECK_DECLS([htole64, le64toh], [], [], [

src/cpu.c

@@ -1,28 +1,35 @@
 #define _GNU_SOURCE
 
-#include <unistd.h>
-
 #include "config.h"
 
 #ifdef HAVE_SCHED_GETAFFINITY
-
 #include <sched.h>
-#include <stdio.h>
+#endif
+
+#ifdef HAVE_SYSCONF
+#include <unistd.h>
+#endif
+
+#ifdef HAVE_GETSYSTEMINFO
+#include <sysinfoapi.h>
+#endif
 
 size_t num_threads(void) {
+#ifdef HAVE_SCHED_GETAFFINITY
     cpu_set_t cpu_set;
     CPU_ZERO(&cpu_set);
-
-    if (sched_getaffinity(0, sizeof cpu_set, &cpu_set) == -1)
-        return sysconf(_SC_NPROCESSORS_ONLN);
-    else
+    if (sched_getaffinity(0, sizeof cpu_set, &cpu_set) == 0)
         return CPU_COUNT(&cpu_set);
-}
-
-#else
+#endif
 
-size_t num_threads(void) {
+#ifdef HAVE_SYSCONF
     return sysconf(_SC_NPROCESSORS_ONLN);
-}
-
+#elif HAVE_GETSYSTEMINFO
+    SYSTEM_INFO sysinfo;
+    GetSystemInfo(&sysinfo);
+    return sysinfo.dwNumberOfProcessors;
+#else
+#warning "No processor-detection enabled! Assuming 2 CPUs"
+    return 2;
 #endif
+}