Re: bin/40115: make(1) behaviour is inconsistent across parallel and ordinary builds

[Aleksej Saushev <asau%inbox.ru@localhost>]

The following reply was made to PR bin/40115; it has been noted by GNATS.

From: Aleksej Saushev <asau%inbox.ru@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost
Subject: Re: bin/40115: make(1) behaviour is inconsistent across parallel and 
ordinary builds
Date: Sun, 07 Dec 2008 11:02:33 +0300

 christos%zoulas.com@localhost (Christos Zoulas) writes:
 
 >  This is not a bug. When -j is present, make tries to execute multiple
 >  shell commands in a single shell instance for efficiency. This is not
 >  very well documented in the man page, but -B gives a hint about it.
 >  If you want to execute each line in its own shell process, use -B.
 >  Most shell snippets that don't cd or chdir, benefit from the new way
 >  of execution.
 
 I'd rather say, it isn't documented at all. The respective parts read:
 
 -B
    Try to be backwards compatible by executing a single shell per
    command and by executing the commands to make the sources of a
    dependency line in sequence.
 
 -j max_jobs
    Specify the maximum number of jobs that make may have running at
    any one time.  Turns compatibility mode off, unless the B flag is
    also specified.
 
 That "try to be backwards compatible by executing a single shell per
 command" gives only a delicate hint, which is far from obvious. In my
 opinion "-j" part should mention it explicitly: "All commands associated
 with [particular? - fix style, please!] target are executed in single
 shell invocation."
 
 Why is it backwards compatible mode, which is on by default?
 Why don't make make run commands in single shell invocation
 and request explicit backward compatibility? Does it break
 too much code?
 
 
 -- 
 HE CE3OH...