[Bug libstdc++/109926] New: fatal error: fenv.h: No such file or directory for canadian compilation of i586-msdosdjgpp

[Bug libstdc++/109926] New: fatal error: fenv.h: No such file or directory for canadian compilation of i586-msdosdjgpp

[unlvsur at live dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109926

            Bug ID: 109926
           Summary: fatal error: fenv.h: No such file or directory for
                    canadian compilation of i586-msdosdjgpp
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: unlvsur at live dot com
  Target Milestone: ---

Created attachment 55131
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55131&action=edit
i586-msdosdjgpp bug

i586-msdosdjgpp bug

[Bug libstdc++/109926] fatal error: fenv.h: No such file or directory for canadian compilation of i586-msdosdjgpp

[unlvsur at live dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109926

--- Comment #1 from cqwrteur <unlvsur at live dot com> ---
/home/cqwrteur/toolchains_build/gcc_build/x86_64-w64-mingw32/i586-msdosdjgpp/artifacts/hostbuild/x86_64-w64-mingw32/gcc/i586-msdosdjgpp/libstdc++-v3/include/fenv.h:36:16:
fatal error: fenv.h: No such file or directory
   36 | # include_next <fenv.h>
      |                ^~~~~~~~
compilation terminated.
make[4]: *** [Makefile:1928: i586-msdosdjgpp/bits/stdc++.h.gch/O2g.gch] Error 1
make[4]: Leaving directory
'/home/cqwrteur/toolchains_build/gcc_build/x86_64-w64-mingw32/i586-msdosdjgpp/artifacts/hostbuild/x86_64-w64-mingw32/gcc/i586-msdosdjgpp/libstdc++-v3/include'
make[3]: *** [Makefile:576: all-recursive] Error 1

[Bug libstdc++/109926] fatal error: fenv.h: No such file or directory for canadian compilation of i586-msdosdjgpp

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109926

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2023-05-21
             Status|UNCONFIRMED                 |WAITING

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Where are the target header installed?

[Bug libstdc++/109926] fatal error: fenv.h: No such file or directory for canadian compilation of i586-msdosdjgpp

[unlvsur at live dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109926

--- Comment #3 from cqwrteur <unlvsur at live dot com> ---
(In reply to Andrew Pinski from comment #2)
> Where are the target header installed?

The headers are installed in the cross toolchain

[Bug libstdc++/109926] fatal error: fenv.h: No such file or directory for canadian compilation of i586-msdosdjgpp

[unlvsur at live dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109926

--- Comment #4 from cqwrteur <unlvsur at live dot com> ---
(In reply to Andrew Pinski from comment #2)
> Where are the target header installed?

The problem is that djgpp crx does not provide fenv.h

libstdc++ provides a fenv.h, however, the build system cannot find it with
canadian compilation.

[Bug libstdc++/109926] fatal error: fenv.h: No such file or directory for canadian compilation of i586-msdosdjgpp

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109926

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to cqwrteur from comment #4)
> libstdc++ provides a fenv.h, however, the build system cannot find it with
> canadian compilation.

The error comes from the libstdc++ fenv.h

[Bug libstdc++/109926] fatal error: fenv.h: No such file or directory for canadian compilation of i586-msdosdjgpp

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109926

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Please provide the i586-msdosdjgpp/libstdc++-v3/config.log file, not the
top-level one from configuring gcc.

The libstdc++ fenv.h has:

#include <bits/c++config.h>
#if _GLIBCXX_HAVE_FENV_H
# include_next <fenv.h>
#endif

And that check comes from:

    AC_CHECK_HEADERS(fenv.h, ac_has_fenv_h=yes, ac_has_fenv_h=no)

So something is wrong with your config.

[Bug libstdc++/109926] fatal error: fenv.h: No such file or directory for canadian compilation of i586-msdosdjgpp

[unlvsur at live dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109926

--- Comment #7 from cqwrteur <unlvsur at live dot com> ---
Created attachment 55135
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55135&action=edit
config

config

[Bug libstdc++/109926] fatal error: fenv.h: No such file or directory for canadian compilation of i586-msdosdjgpp

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109926

--- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Comment on attachment 55135
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55135
config

configure:18893: checking fenv.h usability
configure:18893:  i586-msdosdjgpp-c++     -c -g -O2 -std=c++11 -fno-exceptions 
conftest.cpp >&5
configure:18893: $? = 0
configure:18893: result: yes
configure:18893: checking fenv.h presence
configure:18893:  i586-msdosdjgpp-c++     -E  conftest.cpp
configure:18893: $? = 0
configure:18893: result: yes
configure:18893: checking for fenv.h
configure:18893: result: yes

This means configure is finding fenv.h in your sysroot.

[Bug libstdc++/109926] fatal error: fenv.h: No such file or directory for canadian compilation of i586-msdosdjgpp

[unlvsur at live dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109926

--- Comment #9 from cqwrteur <unlvsur at live dot com> ---
(In reply to Jonathan Wakely from comment #8)
> Comment on attachment 55135 [details]
> config
> 
> configure:18893: checking fenv.h usability
> configure:18893:  i586-msdosdjgpp-c++     -c -g -O2 -std=c++11
> -fno-exceptions  conftest.cpp >&5
> configure:18893: $? = 0
> configure:18893: result: yes
> configure:18893: checking fenv.h presence
> configure:18893:  i586-msdosdjgpp-c++     -E  conftest.cpp
> configure:18893: $? = 0
> configure:18893: result: yes
> configure:18893: checking for fenv.h
> configure:18893: result: yes
> 
> This means configure is finding fenv.h in your sysroot.

fenv.h is in libstdc++. not in libc. djgpp libc does not provide fenv.h

[Bug libstdc++/109926] fatal error: fenv.h: No such file or directory for canadian compilation of i586-msdosdjgpp

[unlvsur at live dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109926

--- Comment #10 from cqwrteur <unlvsur at live dot com> ---
(In reply to Jonathan Wakely from comment #8)
> Comment on attachment 55135 [details]
> config
> 
> configure:18893: checking fenv.h usability
> configure:18893:  i586-msdosdjgpp-c++     -c -g -O2 -std=c++11
> -fno-exceptions  conftest.cpp >&5
> configure:18893: $? = 0
> configure:18893: result: yes
> configure:18893: checking fenv.h presence
> configure:18893:  i586-msdosdjgpp-c++     -E  conftest.cpp
> configure:18893: $? = 0
> configure:18893: result: yes
> configure:18893: checking for fenv.h
> configure:18893: result: yes
> 
> This means configure is finding fenv.h in your sysroot.

i586-msdosdjgpp-c++ should use i586-msdosdjgpp-gcc to test, not
i586-msdosdjgpp-c++ i think

[Bug libstdc++/109926] fatal error: fenv.h: No such file or directory for canadian compilation of i586-msdosdjgpp

[unlvsur at live dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109926

--- Comment #11 from cqwrteur <unlvsur at live dot com> ---
(In reply to cqwrteur from comment #10)
> (In reply to Jonathan Wakely from comment #8)
> > Comment on attachment 55135 [details]
> > config
> > 
> > configure:18893: checking fenv.h usability
> > configure:18893:  i586-msdosdjgpp-c++     -c -g -O2 -std=c++11
> > -fno-exceptions  conftest.cpp >&5
> > configure:18893: $? = 0
> > configure:18893: result: yes
> > configure:18893: checking fenv.h presence
> > configure:18893:  i586-msdosdjgpp-c++     -E  conftest.cpp
> > configure:18893: $? = 0
> > configure:18893: result: yes
> > configure:18893: checking for fenv.h
> > configure:18893: result: yes
> > 
> > This means configure is finding fenv.h in your sysroot.
> 
> i586-msdosdjgpp-c++ should use i586-msdosdjgpp-gcc to test, not
> i586-msdosdjgpp-c++ i think

https://github.com/gcc-mirror/gcc/blob/6fc84f680d098f82c1c43435fdb206099f0df4df/libstdc%2B%2B-v3/configure#L19263

my guess is that it tries to use detect it by using the cross toolchain's
libstdc++ fenv.h despite fenv.h does not exist. probably need to detect it with
-nostdinc++??