On Sat, Sep 3, 2016 at 10:46 AM, Stefan Behnel <stefan...@behnel.de> wrote: > Erik Bray schrieb am 25.04.2016 um 17:18: >> As some of you already know I've been doing some work on Cython on >> Cygwin [in the process I I'm constantly mixing the two up in speech, >> but maybe in writing I'll do better :)]. >> >> There are several issues with the tests on Cygwin, and that's one >> thing I'll work on. But a major annoyance I've encountered when >> running any tests is a huge number of warnings from gcc such as: >> >> embray@PC-pret-47 ~/src/cython >> $ CFLAGS="-O0" ./runtests.py -vv --no-cpp addloop >> Python 2.7.10 (default, Jun 1 2015, 18:05:38) >> [GCC 4.9.2] >> >> Running tests against Cython 0.24 f68b5bd0fa620d0dc26166bffe5fe42d94068720 >> Backends: c >> >> runTest (__main__.CythonRunTestCase) >> compiling (c) and running addloop ... >> === C/C++ compiler error output: === >> In file included from /usr/include/python2.7/Python.h:58:0, >> from addloop.c:4: >> /usr/include/python2.7/pyport.h:69:27: warning: ISO C90 does not >> support ‘long long’ [-Wlong-long] >> #define PY_LONG_LONG long long >> ^ >> /usr/include/python2.7/pyport.h:793:34: note: in definition of macro >> ‘PyAPI_FUNC’ >> # define PyAPI_FUNC(RTYPE) RTYPE >> ^ >> /usr/include/python2.7/intobject.h:46:21: note: in expansion of macro >> ‘PY_LONG_LONG’ >> PyAPI_FUNC(unsigned PY_LONG_LONG) PyInt_AsUnsignedLongLongMask(PyObject *); >> ^ >> In file included from /usr/include/python2.7/Python.h:58:0, >> from addloop.c:4: >> ... >> >> And so on. >> >> For now an easy workaround is to add -Wno-long-long to the compiler >> flags. But I was curious why I was seeing this in Cygwin but not on >> my Ubuntu system, and here's why: >> >> In runtests.py there is a check >> >> https://github.com/cython/cython/blob/master/runtests.py#L829 >> >> if self.language=='c' and compiler='gcc': >> ext_compile_flags.extend(['-std=c89', '-pedantic']) >> >> where in this case `compiler` is assigned >> `sysconfig.get_config_var('CC')`. On my Linux system this expands to >> "x86_64-linux-gnu-gcc -pthread". Whereas on Cygwin (and probably many >> other systems) it expands simply to "gcc". >> >> I'm guessing that to do what it intended the above line should read >> "and 'gcc' in compiler". > > Yes. > >> But this also raises the question: Why are the tests run with these >> flags? If Python was configured with HAVE_LONG_LONG, then these >> warnings will be inevitable. > > Thanks for bringing this up. Adding "-Wno-long-long" seems the right thing > to do, given that this depends on CPython and not Cython. > > Given that CPython *can* be configured without PY_LONG_LONG support, > however, we should then guard any such code in Cython with HAVE_LONG_LONG, > as CPython does internally, so that it actually compiles without it. > > I would otherwise like to keep those compiler flags, even if they didn't > serve us yet, because it is not intended to put all too many constraints on > the C compiler. Supporting C89, at least whenever possible, would be nice.
An alternative could be to just remove them on cygwin. Or maybe, though I haven't tested this I don't think, changing `-std=c89` to `-std=gnu89`. newlib, which is the libc implementation used by Cygwin, has some bugs in its headers that can crop up in odd ways when using `-std=c<xx>`, but with the GNU extensions it's usually a bit more permissive. _______________________________________________ cython-devel mailing list cython-devel@python.org https://mail.python.org/mailman/listinfo/cython-devel
