Here is a makefile that reproduces it. The makefile is a bit hacky (creates
a directory and calls itself from it); this is just to be able to reproduce
it in a single makefile. The 'else' clause is the relevant one. If you put
the makefile in a reasonable path (I used c:\cygwin\tmp), it will find a, b
and c, but not the long filename.
SHELL=cmd.exe
q=$(1)$(1)$(1)$(1)$(1)
long=$(call q,01234567890123456789)
ifeq ($(findstring $(long),$(shell cd)),)
default:
-mkdir $(long)
$(MAKE) -C $(long) -f ..\Makefile
else
src=..\src\$(long)
$(info $(shell mkdir ..\src) $(shell mkdir $(src)))
files=a b c 0123456789012345678901234567890123456789
$(info $(foreach f,$(files),$(shell echo > $(src)/$(f))))
VPATH=$(src)
default: $(files)
@echo ok
endif
On Mon, May 6, 2013 at 6:22 PM, Eli Zaretskii <e...@gnu.org> wrote:
> > Date: Mon, 6 May 2013 15:45:43 +0200
> > From: Erik Carstensen <mandolae...@gmail.com>
> >
> > I found the problem, there seems to be a limit in VPATH resolution of
> > around 256 characters, where ..\ entries in the path are not collapsed.
> In
> > my example, I ran make from c:\path\very-long-build-dir, and had
> > ..\very-long-src-dir on VPATH; very-long-src-dir and very-long-build-dir
> > were a bit over 200 characters together, so some but not all files in the
> > src dir exceeded the length limit and were not found.
> >
> > I don't know where this limit comes from; if it's a Windows limitation,
> > there's not much we can do. In my example it would have helped to
> collapse
> > the ..\:s in VPATH before resolving files, but it would just move the
> > problem a few characters. I have solved it myself in my use case, by
> > printing a warning when detecting dangerously long paths. I'm not sure if
> > it would make sense for make itself to automatically warn on too long
> paths.
>
> I doubt that it has anything to do with Windows.
>
> I'll look into this, but it would help if you could show a simple
> example that can be used to reproduce this problem.
>
> Thanks.
>
_______________________________________________
Make-w32 mailing list
Make-w32@gnu.org
https://lists.gnu.org/mailman/listinfo/make-w32
