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Re: Bug in sub_proc.c: what to patch?

From: Alessandro Vesely
Subject: Re: Bug in sub_proc.c: what to patch?
Date: Sat, 18 Dec 2004 10:26:50 +0100

Earnie Boyd wrote:
> The make provided by MSYS is a copy of some version of source from Cygwin.

I use my own one, with equally good results.

> > BTW, what about a read-only variable reporting if the shell
> > is unixy? One could then write, e.g.
> >
> >    $(if $(NOT_UNIX),if exist *.obj del *.obj,rm -f *.obj)
> >
> You mean a runtime environment variable?


> Nothing that I would use as a portable method.

On Unix it would just be undefined

> The shell bit would need to be set at runtime.


> Besides, I  could have fileutils installed without a shell and use
> rm -f for RM  anyway.

Having assumed that non-shell users are not required to have fileutils,
a portable makefile cannot take advantage of rm.exe being there.

>  You should be sure to check the predefined variables such as RM,
> CC, etc and set those appropriately based on the runtime environment then
> use the variable in the command.
> <example>
> clean:
>         $(RM) *.obj
> </example>

Hmmm... on Windows it should have been $(call RM,*.obj). In fact the del
command doesn't sport a -f option.

Another often used function is `$(subst /,\,$(1))', which one
needs to build non-unixy command lines with a path on any of
the runnable or the redirected file names. (Assuming that the
makefile always uses forward slashes internally.)

header_generator := $(SOMEDIR)/myfoo.exe
generated_header := $(INCDIR)/bar.h
$(generated_header): $(header_generator)
        $(call slashed,$(header_generator)) > $(call 

Also, if you cannot `test -d foo' you have to resort to testing
`if exist foo\*.*' (which only works on non-empty directories.)
Then, if one day a unixy sh.exe makes its way to a user's PATH,
rather than taking advantage of it, the makefile stops working,
vomiting failures that originate from incompatible command syntax.

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