+/* Allow the use in C++ code. */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* A "processor" in this context means a thread execution unit, that is either
+ - an execution core in a (possibly multi-core) chip, in a (possibly multi-
+ chip) module, in a single computer, or
+ - a thread execution unit inside a core
+ (hyper-threading, see <http://en.wikipedia.org/wiki/Hyper-threading>).
+ Which of the two definitions is used, is unspecified. */
+
+enum nproc_query
+{
+ NPROC_ALL, /* total number of processors */
+ NPROC_CURRENT, /* processors available to the current process */
+ NPROC_CURRENT_OVERRIDABLE /* likewise, but overridable through the
+ OMP_NUM_THREADS environment variable */
+};
+
+/* Return the total number of processors. The result is guaranteed to
+ be at least 1. */
+extern unsigned long int num_processors (enum nproc_query query);
+
+#ifdef __cplusplus
+}
+#endif /* C++ */