Bug 843436 - #define DBL_EPSILON ignored [NEEDINFO]
Summary: #define DBL_EPSILON ignored
Alias: None
Product: Fedora
Classification: Fedora
Component: mingw-headers
Version: 19
Hardware: Unspecified
OS: Unspecified
Target Milestone: ---
Assignee: Erik van Pienbroek
QA Contact: Fedora Extras Quality Assurance
Depends On:
TreeView+ depends on / blocked
Reported: 2012-07-26 10:31 UTC by nucleo
Modified: 2015-02-17 14:22 UTC (History)
5 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2015-02-17 14:22:14 UTC
Type: Bug
erik-fedora: needinfo? (alekcejk)

Attachments (Terms of Use)
scratch build log in rawhide (110.22 KB, text/plain)
2012-07-26 10:31 UTC, nucleo
no flags Details

Description nucleo 2012-07-26 10:31:47 UTC
Created attachment 600476 [details]
scratch build log in rawhide

Description of problem:
"#define DBL_EPSILON     __DBL_EPSILON__" from /usr/lib/gcc/i686-w64-mingw32/4.7.0/include/float.h ignored when building opencv:

Version-Release number of selected component (if applicable):

How reproducible:
Build filed for opencv but this simple test example compiles fine:
#include <float.h>
#include <stdio.h>

int main(void)
    printf("DBL_EPSILON: %d\n", DBL_EPSILON);

Also opencv builds fine if all bundled libs libjasper, libjpeg, libpng, libtiff and zlib built instead of using mingw libs (-DBUILD_ZLIB=ON -DBUILD_TIFF=ON -DBUILD_JASPER=ON -DBUILD_JPEG=ON -DBUILD_PNG=ON)

Actual results:
/builddir/build/BUILD/OpenCV-2.4.2/modules/ts/include/opencv2/ts/ts_perf.hpp:166:89: error: 'DBL_EPSILON' was not declared in this scope

Additional info:
This is what file BUILD/OpenCV-2.4.2/build_win32shared/modules/core/CMakeFiles/opencv_perf_core_pch_dephelp.dir/depend.make contains:

modules/core/CMakeFiles/opencv_perf_core_pch_dephelp.dir/opencv_perf_core_pch_dephelp.cxx.obj: /usr/i686-w64-mingw32/sys-root/mingw/include/float.h

Adding lines 
in /usr/i686-w64-mingw32/sys-root/mingw/include/float.h fixes build, so looks like "#define DBL_EPSILON     __DBL_EPSILON__" from /usr/lib/gcc/i686-w64-mingw32/4.7.0/include/float.h ignored.

Comment 1 Kalev Lember 2012-07-26 10:59:29 UTC
It is missing an '#include <float.h>' in ts_perf.hpp.

Comment 2 nucleo 2012-07-26 11:17:50 UTC
Nothing changed after I added '#include <float.h>' in ts_perf.hpp.
Looks like float.h used even without adding this #include because it builds after modifying /usr/i686-w64-mingw32/sys-root/mingw/include/float.h.

Comment 3 Kalev Lember 2012-07-26 11:55:00 UTC
I took a closer look at this and it's passing "-isystem /usr/i686-w64-mingw32/sys-root/mingw/include" to g++, which overrides the order of gcc's internal includes.

While normally /usr/lib64/gcc/i686-w64-mingw32/4.7.0/include precedes /usr/i686-w64-mingw32/sys-root/mingw/include, the use of -isystem reverses the order.

Apparently with gcc 4.6 and newer, the mingw-w64 headers expect that gcc's include directory always comes first. The #include_next <float.h> in mingw-w64's float.h is guarded by __GNUC__ == 4 && __GNUC_MINOR__ < 6.

Kai, are the float.h headers supposed to still correctly include the other one if the system include directory order is swapped?

Comment 4 Kai Tietz 2012-07-26 13:39:55 UTC
The order of system-include directories is right now fixed.  We expect that gcc's internal include comes before the standard include directory.
Of course this might cause issues with -isystem, so a patch for this upstream could be a solution.
Does it help to revome the guard __GNUC__ == 4 && _GNUC_MINGW_ < 6?

Comment 5 nucleo 2012-07-26 17:41:59 UTC
(In reply to comment #4)
> The order of system-include directories is right now fixed.  We expect that
> gcc's internal include comes before the standard include directory.
> Of course this might cause issues with -isystem, so a patch for this
> upstream could be a solution.
> Does it help to revome the guard __GNUC__ == 4 && _GNUC_MINGW_ < 6?

I modified /usr/i686-w64-mingw32/sys-root/mingw/include/float.h:

--- float.h.orig        2012-07-05 21:54:45.000000000 +0300
+++ float.h     2012-07-26 20:37:54.216850282 +0300
@@ -13,7 +13,7 @@
 #if (defined (__GNUC__) && defined (__GNUC_MINOR__)) \
     || (defined(__clang__) && defined(__clang_major__))
-#if (__GNUC__ < 4  || (__GNUC__ == 4 && __GNUC_MINOR__ < 6)) \
+#if (__GNUC__ < 4  ) \
     || (__clang_major__ >=3)
 #if !defined(_FLOAT_H___) && !defined(__FLOAT_H)
 #include_next <float.h>

But compilation failed with the same error:

In file included from /home/user/rpmbuild/BUILD/OpenCV-2.4.2/modules/ts/include/opencv2/ts/ts.hpp:583:0,
                 from /home/user/rpmbuild/BUILD/OpenCV-2.4.2/modules/core/perf/perf_precomp.hpp:8,
                 from /home/user/rpmbuild/BUILD/OpenCV-2.4.2/build_win32shared/modules/core/opencv_perf_core_pch_dephelp.cxx:1:
/home/user/rpmbuild/BUILD/OpenCV-2.4.2/modules/ts/include/opencv2/ts/ts_perf.hpp:163:88: error: 'DBL_EPSILON' was not declared in this scope

Comment 6 nucleo 2012-07-26 20:27:37 UTC
The only place where I found -isystem is cmake/OpenCVPCHSupport.cmake, but looks like -isystem added even after removing line "sed -i '/_PCH_isystem_prefix/d' cmake/OpenCVPCHSupport.cmake".

Comment 7 nucleo 2012-07-27 19:45:18 UTC
I placed files /usr/lib/gcc/i686-w64-mingw32/4.7.0/include/float.h in /usr/i686-w64-mingw32/sys-root/mingw/include/ and /usr/i686-w64-mingw32/sys-root/mingw/include/float.h in /usr/lib/gcc/i686-w64-mingw32/4.7.0/include/ but still getting the same error.

Comment 8 nucleo 2012-08-01 00:43:42 UTC
Now I got other error after this modification of /usr/i686-w64-mingw32/sys-root/mingw/include/float.h:

--- float.h.orig        2012-07-05 21:54:45.000000000 +0300
+++ float.h     2012-08-01 03:39:20.474592779 +0300
@@ -13,8 +13,6 @@
 #if (defined (__GNUC__) && defined (__GNUC_MINOR__)) \
     || (defined(__clang__) && defined(__clang_major__))
-#if (__GNUC__ < 4  || (__GNUC__ == 4 && __GNUC_MINOR__ < 6)) \
-    || (__clang_major__ >=3)
 #if !defined(_FLOAT_H___) && !defined(__FLOAT_H)
 #include_next <float.h>
@@ -113,7 +111,6 @@
        #define _FLOAT_H___
 #ifndef _MINGW_FLOAT_H_
 #define _MINGW_FLOAT_H_

New build error:

In file included from /usr/i686-w64-mingw32/sys-root/mingw/include/float.h:17:0,
                 from /home/user/rpmbuild/BUILD/OpenCV-2.4.2/modules/core/include/opencv2/core/types_c.h:58,
                 from /home/user/rpmbuild/BUILD/OpenCV-2.4.2/modules/core/include/opencv2/core/core.hpp:49,
                 from /home/user/rpmbuild/BUILD/OpenCV-2.4.2/modules/core/src/precomp.hpp:50,
                 from /home/user/rpmbuild/BUILD/OpenCV-2.4.2/build_win32shared/modules/core/opencv_core_pch_dephelp.cxx:1:
/usr/lib/gcc/i686-w64-mingw32/4.7.0/include/float.h:279:24: fatal error: float.h: No such file or directory

Comment 9 nucleo 2012-08-01 08:48:05 UTC
If I additionally to changes from Comment 8 remove this line in file /usr/lib/gcc/i686-w64-mingw32/4.7.0/include/float.h:

#include_next <float.h>

then it compiles fine.

So maybe possible fix needs adding some kind of ifdefs for #include_next in /usr/lib/gcc/i686-w64-mingw32/4.7.0/include/float.h and modification of ifdefs in /usr/i686-w64-mingw32/sys-root/mingw/include/float.h ?

Comment 10 Fedora End Of Life 2013-04-03 14:50:59 UTC
This bug appears to have been reported against 'rawhide' during the Fedora 19 development cycle.
Changing version to '19'.

(As we did not run this process for some time, it could affect also pre-Fedora 19 development
cycle bugs. We are very sorry. It will help us with cleanup during Fedora 19 End Of Life. Thank you.)

More information and reason for this action is here:

Comment 11 Erik van Pienbroek 2014-05-29 13:32:23 UTC
Is this issue still valid on modern Fedora environments?
I can't build the SRPM you mentioned here as it depends on cuda which isn't in Fedora and I don't know where its RPM package can be found

Comment 12 Fedora End Of Life 2015-01-09 17:17:00 UTC
This message is a notice that Fedora 19 is now at end of life. Fedora 
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longer maintained. Approximately 4 (four) weeks from now this bug will
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Comment 13 Fedora End Of Life 2015-02-17 14:22:14 UTC
Fedora 19 changed to end-of-life (EOL) status on 2015-01-06. Fedora 19 is
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