Re: [RFC]serialize the output of parallel make?

[Paul Smith]

On Fri, 2010-07-30 at 09:59 +0800, Chiheng Xu wrote:
> As parallel make are becoming more and more popular,  can make
> serialize the output of parallel make?
> 
> Make can redirect every parallelly issued shell's output to an
> temporary file,  and output the stored output serially, as if in a
> serial make.

This would be a good thing, but as always the details are not quite so
trivial.

We have to ensure that these temporary files are cleaned up properly,
even in the face of users ^C'ing their make invocations.  We also need
to verify that whatever methods we use will work properly on Windows and
VMS and other operating systems make supports (where are their "/tmp"
equivalents?)

And, what about stdout vs. stderr?  Should we write both to the same
file?  Then we lose the ability to do things like "make -j4 2>/dev/null"
since all output will be written to stdout (presumably).  Or should we
keep two files per command, one for stdout and one for stderr?  But
that's even worse since then when we printed it we'd have to print all
the stdout first then all the stderr, which could lose important
context.

Then there's the possibility that some commands will behave differently
if they are writing to a TTY, then they will if they're writing to a
file.  Do we not care about that, or do we try to do something crazy
with PTYs or similar (ugh!)

And of course we have to have a guaranteed unique naming strategy in
case multiple instances of make are running on the same system at the
same time, maybe running the same makefiles and even building the same
targets.  On POSIX systems we can use tmpfile() or mkstemp() or
something but other systems might need other measures.

These are just some things I thought of off the top of my head.

It certainly does not mean that it would not be a good thing to have
this ability though.

-- 
-------------------------------------------------------------------------------
 Paul D. Smith <address@hidden>          Find some GNU make tips at:
 http://www.gnu.org                      http://make.mad-scientist.net
 "Please remain calm...I may be mad, but I am a professional." --Mad Scientist