New function num-processors

This addresses a FIXME comment in lisp/emacs-lisp/comp.el,
relating to the number of subsidiary processes used by
comp-run-async-workers in native compilation.
* admin/merge-gnulib (GNULIB_MODULES): Add nproc.
* doc/lispref/processes.texi (Process Information), etc/NEWS:
Document num-processors.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* lib/nproc.c, lib/nproc.h, m4/nproc.m4:
New files, copied from Gnulib by admin/merge-gnulib.
* lisp/emacs-lisp/comp.el (w32-get-nproc): Remove decl.
(comp-effective-async-max-jobs): Use num-processors.
* src/process.c: Include nproc.h.
(Fnum_processors): New function.
(syms_of_process): Define ‘all’, ‘current’, ‘num-processors’.
* src/w32proc.c (Fw32_get_nproc): Add FIXME comment.
* test/src/process-tests.el (process-num-processors): New test.

1 files changed, 18 insertions, 0 deletions

diff --git a/src/process.c b/src/process.c
index 221d4c7f6c3..746cdc0428a 100644
--- a/src/process.c
+++ b/src/process.c
@@ -90,6 +90,7 @@ static struct rlimit nofile_limit;
 
 #include <c-ctype.h>
 #include <flexmember.h>
+#include <nproc.h>
 #include <sig2str.h>
 #include <verify.h>
 
@@ -8212,6 +8213,20 @@ integer or floating point values.
   return system_process_attributes (pid);
 }
 
+DEFUN ("num-processors", Fnum_processors, Snum_processors, 0, 1, 0,
+       doc: /* Return the number of processors, a positive integer.
+Each usable thread execution unit counts as a processor.
+By default, count the number of available processors,
+overridable via the OMP_NUM_THREADS environment variable.
+If optional argument QUERY is `current', ignore OMP_NUM_THREADS.
+If QUERY is `all', also count processors not available.  */)
+  (Lisp_Object query)
+{
+  return make_uint (num_processors (EQ (query, Qall) ? NPROC_ALL
+				    : EQ (query, Qcurrent) ? NPROC_CURRENT
+				    : NPROC_CURRENT_OVERRIDABLE));
+}
+
 #ifdef subprocesses
 /* Arrange to catch SIGCHLD if this hasn't already been arranged.
    Invoke this after init_process_emacs, and after glib and/or GNUstep
@@ -8472,6 +8487,8 @@ syms_of_process (void)
   DEFSYM (Qpcpu, "pcpu");
   DEFSYM (Qpmem, "pmem");
   DEFSYM (Qargs, "args");
+  DEFSYM (Qall, "all");
+  DEFSYM (Qcurrent, "current");
 
   DEFVAR_BOOL ("delete-exited-processes", delete_exited_processes,
 	       doc: /* Non-nil means delete processes immediately when they exit.
@@ -8633,4 +8650,5 @@ amounts of data in one go.  */);
   defsubr (&Sprocess_inherit_coding_system_flag);
   defsubr (&Slist_system_processes);
   defsubr (&Sprocess_attributes);
+  defsubr (&Snum_processors);
 }