On Thu, Apr 19, 2001 at 11:38:49PM +1000, Bruce Evans wrote:
> On Thu, 19 Apr 2001, Ruslan Ermilov wrote:
> 
> > Attached is the Makefile that demonstrates the problem.  Run it like this:
> > 
> >     make obj; make all
> > 
> > Then try:
> > 
> >     make install
> > 
> > And then try:
> > 
> >     make -j2 install
> > 
> > Note the difference.  This fixes the problem:
> > 
> > --- Makefile        Thu Apr 19 11:33:04 2001
> > +++ Makefile        Thu Apr 19 11:36:20 2001
> > @@ -8,6 +8,7 @@
> >  beforeinstall: .SILENT
> >     cd ${.CURDIR}; \
> >     ${INSTALL} ${COPY} -m ${NOBINMODE} Makefile ${DESTDIR}/tmp
> > +   cd ${.OBJDIR}
> >     pwd
> >     ${INSTALL} ${COPY} -m ${NOBINMODE} foo ${DESTDIR}/tmp
> > 
> > I'm not sure if this a make(1) bug or a feature, as both NetBSD and
> > OpenBSD behave the same.  But I'm pretty sure this is a bug.  Will?
> 
> This is a feature of parallel make.  Parallel make combines all of
> the commands for each target into a single shell command (if possible?).
> Thus `cd's in one command affect subsequent commands.  This feature
> can be controlled using the undocumented .SINGLESHELL directive.
> Unfortunately, the implementation of .SINGLESHELL is too primitive
> for .SINGELSHELL to be worth using.  Using it is equivalent to using
> -B to turn off -j.
> 
I stand corrected.  The simple demo of this feature would be:

foo: .SILENT
        VARIABLE=value
        echo $${VARIABLE}

BTW, I have found the relevant info in the section 2.2 of the
/usr/share/doc/psd/12.make/ paper:

: Because all the commands are given to a single shell to execute,
: such things as setting shell variables, changing directories, etc.,
                                          ^^^^^^^^^^^^^^^^^^^^
: last beyond the command in which they are found. This also allows
: shell compound commands (like ``for'' loops) to be entered in a
: natural manner.  Since this could cause problems for some makefiles
: that depend on each command being executed by a single shell, PMake
: has a -B flag (it stands for backwards-compatible) that forces each
: command to be given to a separate shell. It also does several other
: things, all of which I discourage since they are now old-fashioned.


Thanks,
-- 
Ruslan Ermilov          Oracle Developer/DBA,
[EMAIL PROTECTED]           Sunbay Software AG,
[EMAIL PROTECTED]          FreeBSD committer,
+380.652.512.251        Simferopol, Ukraine

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