Thank you Claus! I've incorporated your section exactly as written. It'll be in the next release of GHC. Simon | -----Original Message----- | From: Claus Reinke [mailto:claus.reinke@talk21.com] | Sent: 31 January 2003 00:40 | To: glasgow-haskell-users@haskell.org | Subject: Re: ghc/cygwin filename resolution issue. | | >As Simon M says, if you (or anyone else) felt able to write up a | >standalone summary of what the problem is, and what the solution is, I'd love | >to add it to the GHC FAQ or documentation somewhere. | | Following the worse-is-better approach, here's some text for others | to fiddle with (I'd recommend to keep the result in the GHC FAQ | proper, possibly with a link from the building guide, if necessary). | I've omitted the build-ghc-with-cygwin option, lest readers in search | or solutions rush of to cause themselves even more problems;-). | | Cheers, | Claus | | Using GHC (and other GHC-compiled executables )with cygwin | ================================================ | | [background] | The cygwin tools aim to provide a unix-style API on top of the windows | libraries, to facilitate ports of unix software to windows. To this end, they | introduce a unix-style directory hierarchy under some root directory | (typically / is C:\cygwin\). Moreover, everything built against the cygwin | API (including the cygwin tools and programs compiled with cygwin's | ghc) will see / as the root of their file system, happily pretending to work | in a typical unix environment, and finding things like /bin and /usr/include | without ever explicitly bothering with their actual location on the windows | system (probably C:\cygwin\bin and C:\cygwin\usr\include). | | [the problem] | GHC, by default, no longer depends on cygwin, but is a native windows | program. It is built using mingw, and it uses mingw's ghc while compiling | your Haskell sources (even if you call it from cygwin's bash), but what | matters here is that - just like any other normal windows program - neither | GHC nor the executables it produces are aware of cygwin's pretended | unix hierarchy. GHC will happily accept either '/' or '\' as path separators, | but it won't know where to find /home/joe/Main.hs or /bin/bash or the | like. This causes all kinds of fun when GHC is used from within cygwin's | bash, or in make-sessions running under cygwin. | | [things to do] | 0) don't panic! | | 1) don't use absolute paths in make, configure & co if there is any chance | that those might be passed to GHC (or to GHC-compiled programs). Relative | paths are fine because cygwin tools are happy with them and GHC accepts | '/' as path-separator. And relative paths don't depend on where cygwin's | root directory is located, or on which partition or network drive your source | tree happens to reside, as long as you 'cd' there first. | | 2) if you have to use absolute paths (beware of the innocent-looking | ROOT=`pwd` in makefile hierarchies or configure scripts), cygwin provides | a tool called 'cygpath' that can convert cygwin's unix-style paths to their | actual windows-style counterparts. Many cygwin tools actually accept | absolute windows-style paths (remember, though, that you either need | to escape '\' or convert '\' to '/'), so you should be fine just using those | everywhere. If you need to use tools that do some kind of path-mangling | that depends on unix-style paths (one fun example is trying to interpret ':' | as a separator in path lists..), you can still try to convert paths using | cygpath just before they are passed to GHC&friends. | | 3) if you don't have cygpath, you probably don't have cygwin and hence | no problems with it.. unless you want to write one build process for several | platforms. Again, relative paths are your friend, but if you have to use | absolute paths, and don't want to use different tools on different platforms, | you can simply write a short Haskell program to print the current directory | (thanks to George Russell for this idea): compiled with GHC, this will give | you the view of the file system that GHC depends on (which will differ | depending on whether GHC is compiled with cygwin's gcc or mingw's | gcc or on a real unix system..) - that little program can also deal with | escaping '\' in paths. Apart from the banner and the startup time, | something like this would also do: | | $ echo "Directory.getCurrentDirectory >>= putStrLn . init . tail . show " | ghci | | 4) panic now. | | | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users@haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users