Re: multi-threaded compiling

[Greg Wooledge]

On Tue, Mar 12, 2024 at 09:42:22AM +0100, Mischa Baars wrote:
> Here's the script and the Makefile using "printf '<%s>'":

Sadly, your mail user agent chose to attach "Makefile" with content-type
application/octet-stream, which my MUA (mutt) refuses to show inline,
or to include in a reply as quoted text.

Here's the top part of it, inline:


STR[0]="one and two"
STR[1]=one\ and\ two

CFLAGS[0]=-D__STRINGIZED__=0 -D__STRING__=${STR[0]}
CFLAGS[1]=-D__STRINGIZED__=0 -D__STRING__=${STR[1]}
CFLAGS[2]=-D__STRINGIZED__=1 -D__STRING__=${STR[0]}
CFLAGS[3]=-D__STRINGIZED__=1 -D__STRING__=${STR[1]}


And here's what Martin said about it:

> On Tue, Mar 12, 2024 at 9:32 AM Martin D Kealey <martin@kurahaupo.gen.nz>
> wrote:
> > In section two, the problem is that quote removal is done BEFORE variables
> > are expanded, even though it prevents word splitting from being done AFTER
> > variable expansion. Therefore writing VAR=" \"string 1\" \"string 2\" "
> > absolutely cannot do what you might expect; the embedded quote marks will
> > be used literally, and then (because ${CFLAGS[0]} is not quoted) the
> > resulting string will be split on any embedded whitespace..


As someone said yesterday, you will need eval for this.


hobbit:/tmp/x$ cat Makefile
FOO=-D__x="one two three"

all:
        @bash -c 'eval '\''CFLAGS=${FOO}'\''; declare -p CFLAGS'
hobbit:/tmp/x$ make
declare -- CFLAGS="-D__x=one two three"


Of course, using eval presents its own set of challenges, so proceed
with extreme caution.

I'd still like to hear why you aren't simply using "make -j".