Doesn't work with MinGW-w64

Question

Doesn't work with MinGW-w64

eXpl0it3r opened this issue 8 years ago · comments

Lukas Dürrenberger commented 8 years ago

It looks like readdir_r is not supported by MinGW-w64 distributions. When I try to build the samples on my MinGW Builds 5.3.0 compiler, I get the following errors.

In file included from tinydir\samples\file_open_sample.c:2:0:
tinydir/tinydir.h: In function 'tinydir_open':
tinydir/tinydir.h:194:10: error: implicit declaration of function 'readdir_r' [-Werror=implicit-function-declaration]
  error = readdir_r(dir->_d, dir->_ep, &dir->_e);
          ^
tinydir/tinydir.h: In function '_tinydir_dirent_buf_size':
tinydir/tinydir.h:629:13: error: #error "buffer size for readdir_r cannot be determined"
 #           error "buffer size for readdir_r cannot be determined"
             ^

Is there an alternative?

Cong · Answer 1 · Wed Mar 30 2016 18:26:59 GMT+0800 (China Standard Time)

Some options, from easiest to hardest:

Use a version of tinydir before the readdir_r changes were made, i.e. https://github.com/cxong/tinydir/tree/74564450519c965f9395f132d1425e904be2b41a
Use preprocessor magic to detect whether readdir_r is absent, and use the plain readdir implementation if this is so
Wait until MinGW implements readdir_r

HTH

Lukas Dürrenberger · Answer 2 · Wed Mar 30 2016 18:47:35 GMT+0800 (China Standard Time)

Thanks for the quick answers, guess I'll go with option one for now.

Cong · Answer 3 · Wed Mar 30 2016 18:57:01 GMT+0800 (China Standard Time)

No problem, thanks for raising the issue 👍 While I have your attention, I've made a quick fix that falls back to readdir for mingw; I've tested on my installation but I'm not sure if it's mingw-w64 - not too familiar with this environment. Could you please try this one out?

Note that readdir may not be threadsafe, so make sure that your program only ever uses one tinydir_dir at a time.

Lukas Dürrenberger · Answer 4 · Wed Mar 30 2016 19:07:06 GMT+0800 (China Standard Time)

That's a fast turnaround. Unfortunately the tests fail to compile with the follow error:

tinydir/tinydir.h:290:6: error: inlining failed in call to 'tinydir_close': call is unlikely and code size would grow [-Werror=inline]
 void tinydir_close(tinydir_dir *dir)
      ^
tinydir/tinydir.h:180:2: error: called from here [-Werror=inline]
  tinydir_close(dir);
  ^

Cong · Answer 5 · Wed Mar 30 2016 19:41:10 GMT+0800 (China Standard Time)

Please try again; however I've discovered that the readdir_r implementation uses a lot of semi-standard functions that may not be available depending on compiler flags; e.g. it doesn't seem to work if -std=c99 is set. If it doesn't work, could you please show your compiler flags?

Lukas Dürrenberger · Answer 6 · Wed Mar 30 2016 19:49:51 GMT+0800 (China Standard Time)

It's still going the #else branch and trying to force inlining with __inline__. Why can't you just use the inline keyword by default? Or is that not standard C?

Here's the command line CMake generates:

bin\gcc.exe   @CMakeFiles/file_open_sample.dir/includes_C.rsp -O3 -DNDEBUG   -fsigned-char -Wall -W -Wshadow -Wstrict-prototypes -Wpointer-arith -Wcast-qual -Winline -Werror -o CMakeFiles\file_open_sample.dir\file_open_sample.c.obj   -c tinydir\samples\file_open_sample.c
tinydir\samples\file_open_sample.c:2:0:
tinydir/tinydir.h: In function 'main':
tinydir/tinydir.h:292:6: error: inlining failed in call to 'tinydir_close': call is unlikely and code size would grow [-Werror=inline]
 void tinydir_close(tinydir_dir *dir)
      ^

Cong · Answer 7 · Wed Mar 30 2016 20:19:01 GMT+0800 (China Standard Time)

inline is standard C but only from C99 onward. I'll see if I can fix up that macro. What version of GCC are you using? I'm surprised that the macro doesn't work, since GCC should have STDC_VERSION.

Lukas Dürrenberger · Answer 8 · Wed Mar 30 2016 20:30:02 GMT+0800 (China Standard Time)

I see. I'm using GCC 5.3.0 from MinGW Builds which uses MinGW-w64.

Cong · Answer 9 · Thu Mar 31 2016 20:17:31 GMT+0800 (China Standard Time)

Unfortunately I still can't reproduce the inline error. Here's what I tried:

Download and install MinGW-w64 for Windows, using mingw-w64-install.exe from https://sourceforge.net/projects/mingw-w64/
Install with GCC 5.3.0 / i686 / posix threads / dwarf exceptions

Under tinydir/samples, run cmake -G"MinGW Makefiles" . && mingw32-make; here's some output from the console:

-- The C compiler identification is GNU 5.3.0
-- Check for working C compiler: C:/Program Files (x86)/mingw-w64/i686-5.3.0-posix-dwarf-rt_v4-rev0/mingw32/bin/gcc.exe
-- Check for working C compiler: C:/Program Files (x86)/mingw-w64/i686-5.3.0-posix-dwarf-rt_v4-rev0/mingw32/bin/gcc.exe -- works

So maybe I'm still using a different environment. You said you use MinGW Builds - how did you manage to get GCC 5.3.0; according to http://mingw-w64.org/doku.php/download the latest is 4.9.2?

Lukas Dürrenberger · Answer 10 · Thu Mar 31 2016 20:25:43 GMT+0800 (China Standard Time)

Oh my bad, for some reason I didn't pull down the macro changes (maybe I was in the wrong directory?), anyways I just updated and it seems to work fine now. 👍

I've installed the same compiler, as you then. The MinGW-w64 project's website seems to not get updated very often.

Thanks for the quick fix and sorry again that you had to spend your time checking the compiler yourself.

Cong · Answer 11 · Thu Mar 31 2016 21:14:30 GMT+0800 (China Standard Time)

No problem, thanks for following up 😎