Re: [ANNOUNCEMENT] Updated: experimental package: gcc4-4.3.2-2

[Dave Korn <dave dot korn dot cygwin at googlemail dot com>]

Angelo Graziosi wrote:
> Still continuing to test...
> 
> Marco Atzeri wrote:
>> if I had ./test_program I see the output on the screen but
>>
>> ./test_program > test_output
>> leave test_output empty.
> 
> If I build that tst case with:
> 
> gfortran-4 test_program.F -o test_program
> 
> then
> 
> $ ./test_program.exe
> SUCCESS
> 
> $ ./test_program.exe > test_output
> 
> $ cat test_output
> SUCCESS

  Hmm, doesn't work here.  1.5 or 1.7?  This is 1.7:

admin@ubik /tmp/fortran/hw
$ cat hw.F
      program main
      WRITE(*,*)     'SUCCESS'
      end

admin@ubik /tmp/fortran/hw
$ gfortran-4 hw.F -o test_program

admin@ubik /tmp/fortran/hw
$ ./test_program.exe  > test_output

admin@ubik /tmp/fortran/hw
$ cat test_output

admin@ubik /tmp/fortran/hw
$ cygcheck ./test_program.exe
F:\cygwin-1.7\tmp\fortran\hw\test_program.exe
  F:\cygwin-1.7\bin\cygwin1.dll
    C:\WINNT\system32\ADVAPI32.DLL
      C:\WINNT\system32\NTDLL.DLL
      C:\WINNT\system32\KERNEL32.DLL
      C:\WINNT\system32\RPCRT4.DLL
  F:\cygwin-1.7\bin\cyggcc_s-1.dll
  F:\cygwin-1.7\bin\cyggfortran-3.dll

admin@ubik /tmp/fortran/hw

> But if I build with:
> 
> gfortran-4 -shared test_program.F -o test_program
> 
> then
> 
> $ ./test_program.exe
> bash: ./test_program.exe: Permission denied
> 
> i.e. it does not work at all!
> 
> What am I missing?

  -shared is not (surprisingly) the opposite of -static!

  -static means link your app against static libs, not DLLs.
  -shared means build your app as a DLL, not an EXE!

  In particular, if you have '-shared', gcc adds '-e __cygwin_dll_entry@12' to
the linker flags, which means that it gets a DllMain function for its
entrypoint instead of your standard main(argc, argv).

  If you want to link against shared DLLs, you need add no options at all;
that's the default for all the languages (except plain C).

    cheers,
      DaveK

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