RE: Autoconf : Build fails if the build and source directory are on different file systems.

[Mat Hounsell]

Maybe not.

However several other file systems were mentioned in discussions as not
supporting symbolic links. FAT16, FAT32 and NTFS would be the most common HDD
file systems in the world. And since autoconf exists to enable you to build
without worrying about OS details then it would probablely be helpful.

 --- Dan Kegel <address@hidden> wrote: 
> Not sure supporting FAT16 is worth spending much time on...
> - Dan
> 
> -----Original Message-----
> From: Mat Hounsell
> To: address@hidden
> Sent: 03.06.2002 18:33
> Subject: Autoconf : Build fails if the build and source directory are on
> different file systems.
> 
> Hello,
>     While trying to build GCC 3.1 for Linux on my home machine I had the
> source
> directory on the EXT2 '/' file system and the build directory on a FAT16
> file
> system with more free space. When I tried to build it failed as
> LIBSTDC++ tries
> to create a link to the source files, which is not supported.
> 
> The problem is in a generated config script 'config.status (?)' that
> tries ln
> -s, then ln then gives up.
> 
> The generated makefiles use ln -s, ln, cp -p then gives up, and had no
> problems.
> 
> The GCC maintainers tracked it probablely down to AC_PROG_LN_S.
> 
> Considering many home users may attempt something like I did, poerhaps
> the
> macro should expand to ln -s , ln , cp -p, cp then give up.
> 
> I am not familiar with the details of autoconf so I thought I would
> raise the
> issue and leave it to those who know.
> 
> --- Original Message ---
> 
> PR: 6776
> LibSTDC++ will cause a GCC 3.1 build to fail if the build and source
> directory
> are on different file systems. This is because it tries to create a hard
> link
> from a header file to the build directory and doesn't gracefully handle
> the
> failure. I tried to copy the file, assuming that make would see the file
> and
> not try to create the link. It tried to create the link anyway and this
> time
> failed as the file exists. If creating a link fails then IMO copying the
> file
> is a good way to overcome the error. It will be removed when the build
> is
> cleaned. I looked in the generated make file and there are macros naming
> the
> files but the macros are never used. Since GCC's build system is
> unfamiliar and
> more advanced then I fully understand, does anyone know how to overcome
> this
> problem? A hack is acceptable. Otherwise, does anyone know where to
> start so I
> can try to fix it myself?
> 
> Background: I use my home machine mainly for Games andP rogramming, it
> is a
> mult-boot machine with Win95, Dos, BeOS and Linux. I have Fat16 data
> partitions
> as it is the only file system all OSes handle. I don't have much space
> on my
> Linux partition so that's why the build is on another partition.
> 
> --- Original Response ---
> In this case, the file include/Makefile.am uses constructs like:
>       @LN_S@ $$h ./$${official_name} || true ;
> Where LN_S comes from acinlude.m4:56 (GLIBCPP_CONFIGURE)
>       # Will set LN_S to either 'ln -s' or 'ln'.  With autoconf 2.5x,
> can
>       # also be 'cp -p' if linking isn't available.
>       #ac_cv_prog_LN_S='cp -p'
>       AC_PROG_LN_S
>    
> This appears to be broken. Since this is a standard autoconf macros,
> perhaps
> you can report this on the autoconf list and see what the status is?
> 
> --- Original Response ---
> And as Benjamin wrote in the response to PR 6776, this is from a
> standard
> autoconf macro, AC_PROG_LN_S, which can be 'ln' or 'ln -s' or (depending
> on whether we ever move to 2.50) 'cp'.  If the autoconf macro is causing
> problems, please report it to the autoconf maintainers.
> 
> 
> 
> 
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