About

This repository contains the source code and a Visual Studio 2015 / Visual C++ 14.0 project (easily upgradable to newer versions) for building a static library containing the necessary runtime components for programs converted from Fortran77 to C using the fortran77-to-c source code translator f2c.

The f2c utility is based on the original Fortran77 compiler f77, and therefore the C code generated by it must be linked against it's runtime components libf77 and libi77. Originally these were two separate libraries, but they were at some point combined into a more convenient single library, libf2c.

See also my f2c project, for building the source code translator program.

The f2c utility is still actively maintained and is available at http://www.netlib.org/f2c/. Changelog can be found at http://www.netlib.org/f2c/changes. The source code of the combined runtime library is available as libf2c.zip. Read more in http://www.netlib.org/f2c/README.

The contribution of this repository is the Visual Studio project, the source code is the original libf2c source code available at netlib.org.

Changelog

See http://www.netlib.org/f2c/changes for history of changes in the netlib f2c source, and if you have the translator program run f2c.exe --version to see which version it was built from.

10 Apr 2024

• Updated to latest version of netlib f2c source, version 20240312.
• Released as version 1.2, with release builds of f2c.exe in 32-bit and 64-bit using Visual Studio 2022 (17.9.6) / Visual C++ 14.3 and Windows SDK 10.0.22621.0.

12 Jan 2022

• Updated to latest version of netlib f2c source, version 20200916.
  • The newer 20210928 entry in changes is an update to readme only, i.e. does not change the version number of the f2c program.
  • No relevant changes in the libf2c source since my last version (see below), there is only a single changed script file (comptry.bat) which not used with my build configuration.
• Released as version 1.1, with release builds of libf2c.lib in 32-bit and 64-bit using Visual Studio 2022 / Visual C++ 14.3.

22 Mar 2017

• Initial version, based on netlib f2c source version 20100827.
• Released as version 1.0, with release builds of libf2c.lib in 32-bit and 64-bit using Visual Studio 2015 Update 3 / Visual C++ 14.0.

Building

The repository includes the original unmodified source code of the libf2c utility as provided by netlib.org, so all you have to do is use Visual Studio to build the supplied project libf2c.vcxproj. This produces the static library libf2c.lib, which contains the runtime components you need to link together with your Fortran-to-C converted application. You could typically add the libf2c project to the solution where you have your Fortran-to-C converted projects, and specify a project reference from those projects to libf2c.

The project file is for the older Visual Studio 2015, but you can open it with newest Visual Studio 2022, and also upgrade it to use the newest versions of Platform Toolset and Windows SDK.

If you want to use your own copy of the libf2c source code you just have to get the project file from this repository, and then download the latest version of libf2c.zip from http://www.netlib.org/f2c/ (direct link: http://www.netlib.org/f2c/libf2c.zip). Extract the contents to a subdirectory with name "src". The final step is to rename four files: Change the file extension of all .h0 and .hvc files to .h. This includes the files: sysdep1.h0, signal1.h0, math.hvc and f2c.h0. In version 20240313 there is also a file fio.h0, however ann identical fio.h is also included. You can use the following PowerShell snippet to rename all at once:

Get-ChildItem *.h0, *.hvc | ForEach-Object { Rename-Item $_ -NewName "$($_.BaseName).h" -ErrorAction Ignore }

How the Visual Studio project was created

The following steps describe how the Visual Studio project was created, so by following them you can do it all yourself without using any files from this repository. The steps are based on the VC makefile (makefile.vc) included with the source code, and then a substantial portion of my own trial and error.

1. Prepare the source code:

   1. Download latest version of libf2c.zip from http://www.netlib.org/f2c/ (direct link: http://www.netlib.org/f2c/libf2c.zip).

   2. Extract libf2c.zip to subdirectory "src".

   3. Change file extension of any *.h0 and *.hvc to *.h. This includes sysdep1.h0, signal1.h0, math.hvc and f2c.h0. Use the following PowerShell command to rename all at once:

      Get-ChildItem *.h0, *.hvc | ForEach-Object { Rename-Item $_ -NewName "$($_.BaseName).h" }

2. Create a new project "libf2c" of type static library, without precompiled header.

3. Add all source files, extension .c, to the project, except the following:

   • ctype.c
   • ftell64_.c
   • pow_qq.c
   • qbitbits.c
   • qbitshft.c
   • signbit.c

4. Add all header files, files with extension .h (including those previously renamed from .h0 and .hvc), to the project, except the following:

   • rawio.h

5. Set up generation of arith.h: The compilation of libf2c is designed such that it first needs to build a command line utility arithchk.exe, which then is executed to check the current system, and the information is stored in a header file (arith.h). The content will typically be something like the following when compiling for x86:

   #define IEEE_8087
   #define Arith_Kind_ASL 1
   #define Double_Align
   #define ssize_t long
   #define QNaN0 0x0
   #define QNaN1 0xfff80000

   and something linke this when comiling for x64:

   #define IEEE_8087
   #define Arith_Kind_ASL 1
   #define Double_Align
   #define X64_bit_pointers
   #define LONG_LONG_POINTERS
   #define ssize_t long long
   #define QNaN0 0x0
   #define QNaN1 0xfff80000

   The header file arith.h is included by the source file uninit.c, so it must be generated before this file is being compiled. One (maybe a bit hacky) way of doing this is to create a Pre-Build Event on the project which does more or less the same as the original makefile. It can be something like this, for building Debug x86:

   SET INCLUDE=$(IncludePath)
   SET LIB=$(LibraryPath)
   MKDIR "$(IntermediateOutputPath)" >NUL 2>&1
   cl.exe /DWIN32 /DNDEBUG /D_CONSOLE /DNO_SSIZE_T /DNO_FPINIT /Fo"$(IntermediateOutputPath)\" src\arithchk.c /nologo /link /OUT:"$(IntermediateOutputPath)arithchk.exe" /NOLOGO
   "$(IntermediateOutputPath)arithchk.exe" >src\arith.h
   del "$(IntermediateOutputPath)arithchk.exe"
   del "$(IntermediateOutputPath)arithchk.obj"

   For release configurations you must change from _DEBUG to NDEBUG, although you can probably just stick with release build of arithcheck.exe even when you build your libf2c in debug. In any case, for the configuration building libf2c in x64 you must remove the definition of WIN32 from the arguments to cl.exe.

   For convenience you can also add the generated header file arith.h to the project. You can also add the arithchk.c to the project and set the build option to "Exclude From Build", although it does not make a difference for the build process.

   Note that NO_SSIZE_T directive is not set by the included VC makefile, but it is needed because the typedef of ssize_t, which is a POSIX and not standard C type definition, has been removed starting with Visual Studio 2012.

6. Add the following preprocessor directives on project level:

   _CRT_SECURE_NO_WARNINGS;USE_CLOCK;MSDOS;NO_ONEXIT;NO_My_ctype;NO_ISATTY

For the extra curious

About ctype.h

The header file ctype.h will be used in the build, even though the source file ctype.c is not. The file ctype.h has conditional compilation, checking preprocessor directive NO_My_ctype, for either to include the standard C header with the same name or for implementing it's macro functions of isdigit and isspace. The source file ctype.c is only for defining the preprocessor directive My_ctype_DEF which is checked for in the header to make sure the symbols in the header file are only defined once (defined when compiling ctype.c, extern-declared when including ctype.h from other source files). When building with Visual Studio we can use the standard ctype header, and therefore we define the preprocessor directive NO_My_ctype. Then compilation of ctype.c is then not needed. Actually ctype.h is not needed either, so we can delete it from the source directory to make the compiler search the include paths for the standard ctype header instead. But if the ctype.h file is present in the source directory it will be used, and then we must have preprocessor directive NO_My_ctype defined.

About signed zeros

The description above is for building without the option of signed zeros in write statements on IEEE-arithmetic systems. That requires some additional files.

License

The libf2c source code is under copyright by AT&T, Lucent Technologies and Bellcore, but it's license permits use, copy, modify, and distribute for any purpose and without fee, provided that the copyright notice is included, and that the permission notice and warranty disclaimer appear in supporting documentation. See LICENSE.md.

The Visual Studio project file and other supporting files, including this documention, is also provided for free use.

Authors

Albertony