From 8e297904d80b39cd510ba0cced37acdb9b1aeb89 Mon Sep 17 00:00:00 2001
From: nebuli <nebu@kipple>
Date: Sat, 22 Nov 2014 19:58:24 +0100
Subject: [PATCH 2/4] guix build: Add --max-jobs option (without handling
 code).

* doc/guix.texi: Mention in the docs.
* guix/scripts/build.scm: Extend (show-build-options-help) and
  (%standard-build-options) functions.
---
 doc/guix.texi          |  5 +++++
 guix/scripts/build.scm | 14 ++++++++++++--
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index 2a33cb5..02edee0 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -2676,6 +2676,11 @@ may be helpful when debugging setup issues with the build daemon.
 Allow the use of up to @var{n} CPU cores for the build.  The special
 value @code{0} means to use as many CPU cores as available.
 
+@item --max-jobs=@var{n}
+@itemx -M @var{n}
+Allow at most @var{n} build jobs. The special value @code{0} means to
+create as many jobs as the number of available CPU cores.
+
 @end table
 
 Behind the scenes, @command{guix build} is essentially an interface to
diff --git a/guix/scripts/build.scm b/guix/scripts/build.scm
index 7b7f419..d10b95b 100644
--- a/guix/scripts/build.scm
+++ b/guix/scripts/build.scm
@@ -119,7 +119,9 @@ options handled by 'set-build-options-from-command-line', and listed in
   (display (_ "
       --verbosity=LEVEL  use the given verbosity LEVEL"))
   (display (_ "
-  -c, --cores=N          allow the use of up to N CPU cores for the build")))
+  -c, --cores=N          allow the use of up to N CPU cores for the build"))
+  (display (_ "
+  -M, --max-jobs=N       allow at most N build jobs")))
 
 (define (set-build-options-from-command-line store opts)
   "Given OPTS, an alist as returned by 'args-fold' given
@@ -192,7 +194,15 @@ options handled by 'set-build-options-from-command-line', and listed in
                   (let ((c (false-if-exception (string->number arg))))
                     (if c
                         (apply values (alist-cons 'cores c result) rest)
-                        (leave (_ "~a: not a number~%") arg)))))))
+                        (leave (_ "not a number: '~a' option argument: ~a~%")
+                               name arg)))))
+        (option '(#\M "max-jobs") #t #f
+                (lambda (opt name arg result . rest)
+                  (let ((c (false-if-exception (string->number arg))))
+                    (if c
+                        (apply values (alist-cons 'max-jobs c result) rest)
+                        (leave (_ "not a number: '~a' option argument: ~a~%")
+                               name arg)))))))
 
 
 ;;;
-- 
2.1.2