Compiling G95

• Set the CVS_RSH environment variable to 'ssh'
• Download gcc with the command:

    cvs -d :ext:anoncvs@savannah.gnu.org:/cvsroot/gcc -z 9 co -P \
        -rgcc_4_0_1_release gcc
  

• This version of GCC now stores object files in a directory distinct from the source directories. G95 expects to find gcc object files and libraries in a directory named 'g95' under the main 'gcc' directory. Run the commands:

  cd gcc
  mkdir g95
  cd g95
  

• The gcc 'configure' script must be run in the directory that you expect to receive the object files. Configure gcc with

  full-path-to-configure/configure --enable-languages=c
  

• Run 'make' to build gcc. A full build isn't necessary. If you end up with libbackend.a, and libgcc.a, you've got enough to build g95. If libgcc.a isn't present, try 'make libgcc.a'.
• Download the g95 source and unpack it in some convenient directory.
• Change to the main g95 directory and configure with

  ./configure --prefix=<installation directory> \
              --with-gcc-dir=<path of your GCC directory>
  
  

• Build g95 with 'make' or 'make install' to install in the installation directory.
• Unpack the libf95.a-0.50.tgz, configure and build it to get libf95.a. Make sure --prefix is the same as with g95.
• Do 'make install' to build and install the library.
• The exact name of the executable depends on the platform. Create a convenient symbolic link to this.
• You should now be able to compile fortran 95 programs with g95.

Platform notes

OSX

Compile g95 with CFLAGS=-no-cpp-precomp. This prevents the special preprocessor from kicking in and messing things up.

MinGW

1. Set-up the build tools:
   • Install MinGW-4.1.0.exe to directory C:\MinGW
   • Install MSYS-1.0.10.exe (configure MinGW to work with MSys) to directory C:\msys\1.0
   • Install msysDTK-1.0.1.exe to directory C:\msys\1.0
   • Install bison and flex to directory C:\GnuWin32
   • Install MSVCP60.DLL to directory C:\GnuWin32\bin
2. Set-up the build directories and environment:
   • Start an MSys shell and run the following commands:

          mkdir -p /include/sys /src/G95/gcc/g95
          echo "c:/mingw/include/sys /include/sys">>/etc/fstab
          echo "PATH=$PATH:/c/GnuWin32/bin">>/etc/profile
          exit
         

3. Get and build GCC:
   • Start an MSys shell and run the following commands:

          # download GCC via CVS
          cd /src/G95
          CVS_RSH=ssh
          export CVS_RSH
          cvs -d :ext:anoncvs@savannah.gnu.org:/cvsroot/gcc -z 9 co -P \
                 -rgcc_4_0_1_release gcc
     
     
          # configure GCC for G95
          cd /src/G95/gcc/g95
          /src/G95/gcc/configure --with-gcc \
                                 --with-gnu-ld \
                                 --with-gnu-as \
                                 --host=mingw32 \
                                 --target=mingw32 \
                                 --prefix=/mingw \
                                 --enable-threads \
                                 --disable-nls \
                                 --enable-languages=c \
                                 --disable-win32-registry \
                                 --disable-shared \
                                 --without-x
     
          # build GCC for G95
          make
         

   • If the build fails with the message:

          build/gengtype.exe
          /src/G95/gcc/gcc/input.h: No such file or directory
          make[1]: *** [s-gtype] Error 1
          make[1]: Leaving directory `/src/G95/gcc/g95/gcc'
          make: *** [all-gcc] Error 2
         

   • Run the following commands:

          cp gcc/gtyp-gen.h gcc/gtyp-gen.h.orig
          sed -e "s/^\"\/src/\"c:\/msys\/1.0\/src/g" \
              gcc/gtyp-gen.h.orig>gcc/gtyp-gen.h
          make
         

   • If all goes well this will result in MinGW builds of libbackend.a and libgcc.a needed for compiling g95.
4. Configure the g95 source distribution:
   • Download the g95 source and unpack it within C:\msys\1.0\src\G95
   • Run the following commands:

          cd /src/G95/g95-0.50
          ./configure --prefix=/usr/local --with-gcc-dir=/src/G95/gcc
         

   • Continue with the g95 compilation instructions.

Cygwin

1. Set-up the build tools:
   • Install Cygwin to directory C:\cygwin
2. Set-up the build directory:
   • Start a Cygwin session and run the following command:

      mkdir -p /src/G95/gcc/g95 

3. Get and build GCC:
   • Within the Cygwin session run the following commands:

    # download GCC via CVS
        cd /src/G95
        CVS_RSH=ssh
        export CVS_RSH
        cvs -d :ext:anoncvs@savannah.gnu.org:/cvsroot/gcc -z 9 co -P \
            -rgcc_4_0_1_release gcc
   
        # configure GCC for G95
        cd /src/G95/gcc/g95
        /src/G95/gcc/configure --enable-languages=c \
                               --disable-nls
   
        # build GCC for G95
        make
   

4. If all goes well this will result in Cygwin builds of libbackend.a and libgcc.a needed for compiling g95.
5. Configure the g95 source distribution:
   • Download the g95 source and unpack it within C:\cygwin\src\G95
   • Within the Cygwin session run the following commands:

      cd /src/G95/g95-0.50
      ./configure --prefix=/usr/local --with-gcc-dir=/src/G95/gcc
     

   • Continue with the g95 compilation instructions.

Support of MinGW targets under Cygwin

1. Complete successfully the Cygwin build of G95
2. Configure the G95 library to support MinGW within Cygwin
   • Start an Cygwin session and run the following command:

      cd /src/G95/g95-0.50/libf95.a-0.50
      ./configure --prefix=/usr/local --with-gcc-dir=/src/G95/gcc --with-mingw
       

3. Build the G95 library to support MinGW within Cygwin
   • Within the Cygwin session run the following command:

      rm *.o *.a
      make
       

   • This should result in a re-built libf95.a whose members have been compiled under Cygwin with the -mno-cygwin option enabled.
4. Enable the MinGW compliant library for Cygwin G95:
   • Within the Cygwin session run the following commands:

      mkdir /usr/local/lib/gcc-lib/i686-pc-mingw32/4.0.1/
          ranlib libf95.a
          cp libf95.a /usr/local/lib/gcc-lib/i686-pc-mingw32/4.0.1/
          cd /usr/local/lib/gcc-lib/i686-pc-cygwin/4.0.1/
          g95 -dumpspecs > specs.0
          sed -e '/*startfile:/ {
              n
              s/%{mno-cygwin:dllcrt2%O%s/%{mno-cygwin:\/usr\/lib\/mingw\/dllcrt2%O%s -L\/usr\/local\/lib\/gcc-lib\/i686-pc-mingw32\/4.0.1 -L\/usr\/lib\/mingw/
              s/%{mno-cygwin:crt2%O%s/%{mno-cygwin:\/usr\/lib\/mingw\/crt2%O%s -L\/usr\/local\/lib\/gcc-lib\/i686-pc-mingw32\/4.0.1 -L\/usr\/lib\/mingw/
     	}' specs.0 > specs
          rm specs.0
        

5. The -mno-cygwin should now be supported by Cygwin g95
   Following example Cygwin session output to confirm could be:

    dmiles@STACK02 /tmp
        $ uname
        CYGWIN_NT-5.1
        
        dmiles@STACK02 /tmp
        $ cat hello.f
              program hello
              print *,'hello'
              end
   
        dmiles@STACK02 /tmp
        $ g95 -o hello_cygwin.exe hello.f
        
        dmiles@STACK02 /tmp
        $ ./hello_cygwin
         hello
   
        dmiles@STACK02 /tmp
        $ objdump -x hello_cygwin.exe | grep "DLL Name"
                DLL Name: cygwin1.dll
                DLL Name: cygwin1.dll
                DLL Name: KERNEL32.dll
   
        dmiles@STACK02 /tmp
        $ g95 -mno-cygwin -o hello_mingw.exe hello.f
        
        dmiles@STACK02 /tmp
        $ ./hello_mingw
         hello
   
        dmiles@STACK02 /tmp
        $ objdump -x hello_mingw.exe | grep "DLL Name"
                DLL Name: msvcrt.dll
                DLL Name: msvcrt.dll
                DLL Name: KERNEL32.dl

Build a dll version of g95

A script to download and unpack the g95 source, and build a version of g95 that uses dlls, has been contributed by Dave Miles.

• Your Cygwin environment should be set up to build g95 as described above.
• Save the following script in a file named bld-g95.sh.

#!/bin/sh
{
 cd /src/G95
 rm -fR g95-0.50 
 wget -O - http://www.g95.org/g95_source.tgz | tar xvfz -
 cd g95-0.50 
 ./configure --prefix=/usr/local --with-gcc-dir=/src/G95/gcc
 make
 tar -zxf libf95.a-0.50.tar.gz &&\
 cd libf95.a-0.50 &&\
 ./configure --prefix=/usr/local --with-gcc-dir=/src/G95/gcc &&\
 make  
 if [ $? != 0 ]
 then
  exit
 fi
 make install
 mv main.o main.g95
 gcc -mdll -o g95.dll \
     -Wl,--output-def \
     -Wl,g95.def \
     -Wl,--out-implib \
     -Wl,libf95.dll.a \
     -Wl,--export-all-symbols *.o -lws2_32
 if [ -f libf95.dll.a ]
 then
  cp libf95.dll.a /usr/local/lib/gcc-lib/i686-pc-cygwin/4.0.1/
 fi
 if [ -f g95.dll ]
 then
  cp g95.dll /bin
 fi
 cp main.g95 /lib/g95main.o
 cd ..
 make install
 cd ..
} 2>&1 | tee -a  bld-g95.log

• In a Cygwin bash shell, run the following commands:

chmod +x bld-g95.sh  
./bld-g95.sh  

• When compiling, link to /lib/g95main.o or compile with -shared.