#245: Cabal should support hsc2hs's stub .c feature ----------------------------+----------------------------------------------- Reporter: guest | Owner: Type: defect | Status: new Priority: normal | Milestone: Component: Cabal library | Version: 1.2.3.0 Severity: normal | Resolution: Keywords: | Difficulty: normal Ghcversion: 6.8.2 | Platform: ----------------------------+----------------------------------------------- Changes (by duncan): * summary: Cabal gets paths wrong in INCLUDEs => Cabal should support hsc2hs's stub .c feature Comment: hsc2hs has a little used feature which is that you can use `#def` directives to spit bits of C code into a generated .c and .h file. The build system is supposed to notice this .c file and compile and link it into the system in question. Cabal does not do this (presumably because nobody implementing hsc2hs support had ever seen the feature). Turns out that people were making use of this hsc2hs feature despite the lack of support in Cabal by relying on the fact that Cabal used to put pre-processor output into the src dirs so instead of asking for proper support people worked around the issue by using things like: {{{ c-sources: src/Foo_hsc.c }}} and relying on Cabal to run `hsc2hs` on `src/Foo.hsc` to generate `src/Foo_hsc.c` before compiling any `.c` files. Of course when Cabal-1.2 changed to put all generated files under `dist/` this workaround broke. The right thing obviously is for Cabal to notice the `.c` files that `hsc2hs` generates and to compile and link them in. There may be a problem with paths however since `hsc2hs` will be putting the generated `.c` file under `dist/build/` and `hsc2hs` embeds a '#include` to the `.h` file with the full `dist/build/` prefix, but we do not put `.` on the include search path, only `dist/build/`, so the header file should really be relative to that. This may require changes in hsc2hs to support properly. We got this working correctly for `c2hs` which does similar things, embedding relative links between generated files. -- Ticket URL: http://hackage.haskell.org/trac/hackage/ticket/245#comment:1 Hackage http://haskell.org/cabal/ Hackage: Cabal and related projects