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Compiling

  • When compiling, the compiler doesn't seem to find the correct definitions for a specific Windows version or a specific Internet Explorer version. Why is that?
    • You need to set defines _WIN32_WINDOWS, _WIN32_WINNT, WINVER and/or _WIN32_IE to the minimum platform you plan to support before including the windows.h header file. Possible values for these definitions can be found in the header w32api.h file.
  • My executables large and bloated after compilation. How can I avoid this?
    • The executables large page will teach you how to strip a binary and how to avoid large executables.
  • My executable is sometimes different, when I compile and recompile the same source. Is this normal?
    • Yes, by default, and by design, ~MinGW's GCC does not produce ConsistentOutput, unless you patch it.
  • Why do I get error messages when building a simple program using MinGW?
    • You might have partially installed MinGW: please read error messages.
  • How do I specify the libraries to be searched by the linker?
    • MinGW supports libraries named according to the `<name>.lib' and `<name>.dll' conventions, in addition to the normal `lib<name>.a' convention common on *nix systems. To include any libraries named according to any of these conventions, simply add the `-l<name>' switch to the compiler command, ensuring it is placed _after_ the name of the module in which the reference appears.
    • Note that, if the library is not found in any of the default library search paths, you may also need to insert a `-L<dir>' switch _before_ the `-l<name>' switch, to specify its location.
    • Also note that the library names `lib<name>.a' and `lib<name>.lib' _are not_ equivalent; if you have a library named according to the aberrant `lib<name>.lib' convention, it will not be found by specifying the `-l<name>' switch -- you must use the form `-llib<name>' instead.
  • Why don't wide characters work with libstdc++?
    • The wide-character parts of the GCC Standard C++ Library (libstdc++) have not yet been fully ported to Windows. Alternatives and discussion on this can be found here.
  • How do I correctly use [threads] in MinGW?
    • You should use _beginthreadex instead of ~CreateThread for the reason cited on the threads page.
  • Why can't I MixObjects from different CompilerBrands or MixObjects from different compiler versions of the same compiler brands?
    • This issue is not specific to MinGW: many compilers are mutually incompatible.
  • How do I remove DOS command windows?
    • In the link step add a "-mwindows" switch to the command line.
  • Why does _make_ often crash creating a sh.exe.stackdump file when I try to compile my source code?
    • If you experience random crashes with _make_ as well as with the _msysinfo_ command (_i.e._, repeating the command often allows to compile the source code succesfully), the issue might be caused by the Logitech QuickCam software. Here is provided a solution to this issue:
      • type the command _services.msc_ from a command prompt (you will need administrator privileges to do this), then find the "Logitech Process Monitor" service, and change the "Startup type" from "Auto" to "Manual". Do the same with the "LVSrvLauncher" service.
      • type the command _regedit_ from the command prompt (you will need administrator privileges to do this), then find the key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run. Among the other REG_SZ keys, there should be three of them related to the Logitech QuickCam, namely: "LogitechCommunicationsManager", "LogitechQuickCamRibbon", "LVCOMSX". Make a backup of the registry, then remove them.
      • reboot your PC
        • In this way the Logitech QuickCam deamon won't be available anymore. Nonetheless, the camera will keep working just ok with 3rd party software (_e.g._, Skype). If you want a less drastic solution, just kill the lvprcsrv.exe process whenever you want to use MSYS by typing at the command prompt:
  _pskill -t lvprcsrv.exe_ (you will need [[PsTools]] and administrator privileges to do this). However, as soon as you will plug in the USB cable of your Logitech QuickCam, the deamon will be restarted, while with the first procedure it won't.

Cross Compiling

Compiling Packages

  • How do I build a source package I just downloaded?
    • The PackageGuide contains a link of packages along with the description of the package and a tutorial for compiling it.
  • I didn't modify any configure.in or makefile.in, but the build process still tries to regenerate these files. What should I do?

C / C++

  • How do I create a DLLs?
    • The sample DLL tutorial will teach you how to create and a use a DLLs.
  • How do I create a DLLs for Visual Basic to use?
    • The VB-MinGW-DLL tutorial will teach you how to create a DLL with MinGW and a use it with Visual Basic.

Debugging

Documentation

      groff -Tascii -pet -mandoc -P-c <manpage-file> | less -irs

  To make it more convenient to view manpages, Wu Yongwei has provided these [[scripts|ManScript]], which implement a rudimentary version of a "man" program, for use with MSYS, or in a cmd.exe window.

  Note that you will still need to have "groff" installed, when the full "man" package becomes available, if you wish to use "man" for reading documentation in the manpage format.

Licensing

  • How is MinGW licensed?
    • When Colin Peters released the MinGW runtime he placed the source into the PublicDomain. No one owns a copyright (C) to the source because of this. You as a software manufacturer are free to use the MinGW runtime in your proprietary and OpenSource software as you see fit. The only thing you can't do is to claim ownership of the source and use Colin Peters' name, the MinGW name or the name of any of it's contributors in endorsement of any product.
    • Please view MinGWLicensing for full details.
  • How is MSYS licensed?
    • From MSYS_LICENSE.rtf:

    You may redistribute MSYS in part or in whole as long as you follow the guidelines of redistribution of each license contained within.  To be certain that you are being legally compliant, always distribute the source.  Distribution of source is your responsibility should you decide to redistribute MSYS.     If you distribute MSYS via a web site then you must put a copy of the source for that version of MSYS on your web site as well.  If you distribute MSYS via removable media then you must distribute that version of MSYS source with that same type of removable media.

    Binaries created from the use of MSYS and of MinGW are not bound by any license found within this package unless you use a library that is itself covered by the GPL license.  If you wish to create proprietary software then don't use libiberty.a or any other GPL licensed library.  A library licensed with LGPL (Lesser GPL) may be used by proprietary software without GPL infection as special permission within the LGPL has given you this right.

  So essentially unless you end up explicitly linking against msys-1.0.dll, programs built in MSYS shell using MSYS tools are not infected with GPL. Compiling and linking inside MSYS shell or using MSYS tools alone does not automatically link against the dll. 

    • Please view MSYS_LICENSE.rtf for full license text.

MinGW related

  • What Languages Are Supported?
    • As of summer 2005, MinGW supports C, C++, ObjC, Fortran 77, Ada and Java. And last, but not least Pascal is available as a contributed package (GPC).
  • How do I use MinGW with Cygwin?
    • For those who would like to use the Cygwin environment for development, yet generate non-Cygwin-dependant executables, a much easier option to "-mno-cygwin" does exist. Simply install Cygwin and the MinGW distribution in separate directories (i.e. "C:\CYGWIN" and "C:\MINGW"), and make sure that the "/bin" subdirectory beneath your MinGW installation comes before Cygwin's "/bin" subdirectory in your PATH environment variable (i.e. "PATH=%PATH%;C:\MINGW\BIN;C:\CYGWIN\BIN"). This will allow you access to all the UNIX tools you want, while ensuring that the instance of GCC used is the MinGW version. %%%
    • Bear in mind that within the "/etc/profile" file, Cygwin by default places "/usr/local/bin", "/usr/bin", and "/bin" ahead of your system-level PATH. Therefore, it is not enough to have the MinGW's "/bin" ahead of Cygwin in your Windows path... it must also be set to come first within the Cygwin environment (either by modifying "/etc/profile" or setting it manually).
  • Is support provided for COM?
    • MinGW has some support for COM programs. Programmers have had much better luck writing COM applications in C than C++. Work is in progress to improve support. Check the MinGW mailing list archives for more details on COM and more links to example files.
  • What's the difference between gcc and mingw32-gcc?
    • The mingw32-gcc, mingw32-g++, etc. binaries exist as an aid to cross development. They are created in a typical build of gcc. They are therefore distributed as the maintainers of GCC meant them to be. The gcc.exe indicates that the binary produces binaries for a target equal to the build, while the mingw32-gcc binary produces binaries to be executed on the mingw32 target.
  • What's the difference between make and mingw32-make?
    • The "native" (i.e.: MSVCRT dependent) port of make is lacking in some functionality and has modified functionality due to the lack of POSIX on Win32. There also exists a version of make in the MSYS distribution that is dependent on the MSYS runtime. This port operates more as make was intended to operate and gives less headaches during execution. Based on this, the MinGW developers/maintainers/packagers decided it would be best to rename the native version so that both the "native" version and the MSYS version could be present at the same time without file name collision.
  • How can an MSVC program call a MinGW DLL, and vice versa?
  • How can a JNI DLL be created?
    • A tutorial to create a Java Native Interface DLL can be found here: JNI-MinGW-DLL

MSYS related

  • My programs don't print output; how do I fix this?
  • How do I pass switches with forward slashes to programs under MSYS?
    • Please view page [switches with forward slashes]
  • How do I build an MSYS binary?
    • You must be under a MSYS shell and tools environment to compile. Please refer to MSYS dependent for more information.
  • Why will the MSYS shell not open on Windows XP Professional x64?

Other

  • How do I create Python extensions?
    • As of Python 2.5, the official distribution is built with MS-VC 2003. Python requires that all extensions be built with the same compiler. It is however possible to build such extensions using MinGW with the help of MSYS. Create a file called pydistutils.cfg in your home directory with the following contents.
[build]
compiler=mingw32

  • Next, use pexports to export the python dll symbols. The library can typically be found under C:\WINDOWS\system32. Use the following command.
pexports /c/WINDOWS/system32/python25.dll >py25.def

  • Then, use the following command to build an import library.
dlltool -D python25.dll -d python25.def -l libpython25.a

  • Move libpython25.a to /mingw/lib. You may need to add -I"/path/to/python/include" to the gcc command line. You can now build and install the extensions by following standard UNIX instructions under MSYS.
  • How do I execute configure scripts?
    • Applications using a UNIX-style build process will typically require a shell environment and set of POSIX tools, for executing configure scripts and building the application. The Cygwin environment was once the only choice available to fill this role, although now the MSYS environment offers MinGW developers a more lightweight alternative. The use of both these environments with MinGW is described in MsysShell and MinGWShell. [FIXME] - This is confusing and doesn't describe the question. __EarnieBoyd__ __2006-04-19__
  • What is a Makefile and how do I create one?
    • A Makefile can be thought of as a script that is processed by a "make" program. It allows large projects with many source files to compile in an automated way, as opposed to needing to compile each file by manually calling the compiler. It also allows for depedency checking, recompiling only modified files by checking timestamps.
  • How do I get pkg-config installed?
    • The difficulty in getting pkg-config installed is due its circular depency on glib. To install pkg-config, you should first install the GTK-runtime, the installer is found at http://sourceforge.net/project/showfiles.php?group_id=121075. The pkg-config binary can be obtained from //www.gimp.org/~tml/gimp/win32/downloads.html. Place pkg-config.exe in your MinGW bin directory.

Porting Issues

  • Why doesn't %ll work with printf? How do I print a long long value?
    • You should use %I64 instead of %ll when using msvcrt.
  • Why can't I print a long double using printf using %Lf?
  • How do I use Windows sockets, rather than Unix sockets?
  • Why can I read/write text files but not binary files?
  • gcc supports C99; why is this support not completely implemented in MinGW?

Re: FAQ

The link to where you can get the pkg-config does not exist anymore.

Re: FAQ

Hello, I've two question, two request :
- what about support of GCC 4.x (now 4.5) on MinGW32
- what about building Windows 64 bits executable (for AMD64/Intel EM64T)?

Re: FAQ

keith's picture

And I have just one response: please read the tag line immediately below; if you want to ask questions, USE THE MAILING LIST!

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