nproc: A new program to count the available processors

* AUTHORS: Add my name.
* NEWS: Mention it.
* README: Likewise.
* bootstrap.conf (gnulib_modules): Add nproc.
* doc/coreutils.texi (nproc invocation): Add nproc info.
* man/Makefile.am (nproc.1): Add dependency.
* man/nproc.x: New template.
* man/.gitignore: Ignore generated man page.
* po/POTFILES.in: Add src/nproc.c.
* src/.gitignore: Exclude nproc.
* src/Makefile.am (EXTRA_PROGRAMS): Add nproc.
* src/nproc.c: New file.
* tests/Makefile.am (TESTS): Add misc/nproc-{avail,positive}.
* tests/misc/nproc-avail: New file.
* tests/misc/nproc-positive: New file.

1 files changed, 127 insertions, 0 deletions

diff --git a/src/nproc.c b/src/nproc.c
new file mode 100644
index 000000000..5c7aed1f5
--- /dev/null
+++ b/src/nproc.c
@@ -0,0 +1,127 @@
+/* nproc - print the number of processors.
+   Copyright (C) 2009 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* Written by Giuseppe Scrivano.  */
+
+#include <config.h>
+#include <getopt.h>
+#include <stdio.h>
+#include <sys/types.h>
+
+#include "system.h"
+#include "error.h"
+#include "nproc.h"
+#include "xstrtol.h"
+
+/* The official name of this program (e.g., no `g' prefix).  */
+#define PROGRAM_NAME "nproc"
+
+#define AUTHORS proper_name ("Giuseppe Scrivano")
+
+enum
+{
+  ALL_OPTION = CHAR_MAX + 1,
+  IGNORE_OPTION
+};
+
+static struct option const longopts[] =
+{
+  {"all", no_argument, NULL, ALL_OPTION},
+  {"ignore", required_argument, NULL, IGNORE_OPTION},
+  {GETOPT_HELP_OPTION_DECL},
+  {GETOPT_VERSION_OPTION_DECL},
+  {NULL, 0, NULL, 0}
+};
+
+void
+usage (int status)
+{
+  if (status != EXIT_SUCCESS)
+    fprintf (stderr, _("Try `%s --help' for more information.\n"),
+             program_name);
+  else
+    {
+      printf (_("Usage: %s [OPTION]...\n"), program_name);
+      fputs (_("\
+Print the number of processing units available to the current process,\n\
+which may be less than the number of online processors\n\
+\n\
+"), stdout);
+      fputs (_("\
+     --all       print the number of installed processors\n\
+     --ignore=N  if possible, exclude N processing units\n\
+"), stdout);
+
+      fputs (HELP_OPTION_DESCRIPTION, stdout);
+      fputs (VERSION_OPTION_DESCRIPTION, stdout);
+      emit_ancillary_info ();
+    }
+  exit (status);
+}
+
+int
+main (int argc, char **argv)
+{
+  unsigned long nproc, ignore = 0;
+  initialize_main (&argc, &argv);
+  set_program_name (argv[0]);
+  setlocale (LC_ALL, "");
+  bindtextdomain (PACKAGE, LOCALEDIR);
+  textdomain (PACKAGE);
+
+  atexit (close_stdout);
+
+  enum nproc_query mode = NPROC_CURRENT_OVERRIDABLE;
+
+  while (1)
+    {
+      int c = getopt_long (argc, argv, "", longopts, NULL);
+      if (c == -1)
+        break;
+      switch (c)
+        {
+        case_GETOPT_HELP_CHAR;
+
+        case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
+
+        case ALL_OPTION:
+          mode = NPROC_ALL;
+          break;
+
+        case IGNORE_OPTION:
+          if (xstrtoul (optarg, NULL, 10, &ignore, "") != LONGINT_OK)
+            {
+              error (0, 0, _("%s: invalid number to ignore"), optarg);
+              usage (EXIT_FAILURE);
+            }
+          break;
+
+        default:
+          usage (EXIT_FAILURE);
+        }
+    }
+
+  nproc = num_processors (mode);
+
+  if (ignore < nproc)
+    nproc -= ignore;
+  else
+    nproc = 1;
+
+  printf ("%lu\n", nproc);
+
+  exit (EXIT_SUCCESS);
+}