Full getopt Port for Unicode and Multibyte Microsoft Visual C, C++, or MFC Projects

• Download source - 5.07 KB
• Download Visual Studio 6 ANSI Project - 18.52 KB
• Download Visual Studio 6 MFC Project - 22.79 KB
• Download Visual Studio 2005 .NET ANSI Project - 12.2 KB
• Download Visual Studio 2005 .NET MFC Project - 16.14 KB
• Download Visual Studio 2008 .NET ANSI Project - 12.22 KB
• Download Visual Studio 2008 .NET MFC Project - 16.33 KB
• Download Visual Studio 2010 .NET ANSI Project - 14.0 KB

Introduction

This software was written after hours of searching for a robust Microsoft C and C++ implementation of getopt, which led to devoid results.

This software is a modification of the Free Software Foundation, Inc. getopt library for parsing command line arguments and its purpose is to provide a Microsoft Visual C friendly derivative. The source code provides functionality for both Unicode and Multibyte builds and supports getopt, getopt_long, and getopt_long_only. Additionally the code supports the POSIXLY_CORRECT environment flag. The library utilizes the standard Microsoft C TCHAR definition to toggle between char and wchar_t via the definition of the _UNICODE preprocessor directive.

The original GNU code used several header and implementation files containing numerous preprocessor directives specific to Linux environments which have been removed. After removing unneeded dependencies, it was condensed into a single header and implementation file which can be compiled into a DLL, LIB, or directly included into any Visual C, C++, or MFC project. The getopt library can be used by proprietary software, however; certain measures need to be taken to ensure proprietary code adheres to the Lesser GNU Public License for non-derivative works. Please refer to the licensing section of this article for more details on how this software is licensed.

For the sake of brevity, this article doesn't discuss how to use the getopt functions. Anyone new to using the getopt functions should refer to the GNU tutorial for using getopt.

Licensing

Preprocessor Definitions

Compiling getopt as a Dynamic Link Library (DLL) requires the preprocessor definition of EXPORTS_GETOPT. The definition of EXPORTS_GETOPT sets the internal preprocessor definition _GETOPT_API to the value __declspec(dllexport). Compiling getopt as a Static Library (LIB) or directly including the source and header file within a project requires the preprocessor definition of STATIC_GETOPT. The definition of STATIC_GETOPT clears the value of the internal preprocessor definition of _GETOPT_API. Compiling software to use getopt.dll requires that no library specific preprocessor definitions be used. When no library specific preprocessor definitions are used the value assigned to the internal preprocessor definition _GETOPT_API is __declspec(dllimport).

The code segment below demonstrates the logic outlined above:

#if defined(EXPORTS_GETOPT) && defined(STATIC_GETOPT)
    #error "The preprocessor definitions of EXPORTS_GETOPT 
        and STATIC_GETOPT can only be used individually"
#elif defined(STATIC_GETOPT)
#pragma message("Warning static builds of getopt violate the Lesser GNU Public License")
    #define _GETOPT_API
#elif defined(EXPORTS_GETOPT)
    #pragma message("Exporting getopt library")
    #define _GETOPT_API __declspec(dllexport)    
#else
    #pragma message("Importing getopt library")
    #define _GETOPT_API __declspec(dllimport)
#endif

Sample Code Provided

To help with understanding how to use the code, many versions have been provided for download. The following downloads are provided:

• Visual Studio .NET 2010 ANSI Project
• Visual Studio .NET 2008 ANSI Project
• Visual Studio .NET 2008 MFC Project
• Visual Studio .NET 2005 ANSI Project
• Visual Studio .NET 2005 MFC Project
• Visual Studio 6 ANSI Project
• Visual Studio 6 MFC Project

Using the Code

The code is used identical to GNU getopt.

#include <stdio.h>
#include <stdlib.h>
#include "getopt.h"

int _tmain(int argc, TCHAR** argv)
{
    static int verbose_flag;
    int c;

    while (1)
    {        
        static struct option long_options[] =
        {
            {_T("verbose"), ARG_NONE, &verbose_flag, 1},
            {_T("brief"),   ARG_NONE, &verbose_flag, 0},
            {_T("add"),     ARG_NONE, 0, _T('a')},
            {_T("append"),  ARG_NONE, 0, _T('b')},
            {_T("delete"),  ARG_REQ,  0, _T('d')},
            {_T("create"),  ARG_REQ,  0, _T('c')},
            {_T("file"),    ARG_REQ, 0 , _T('f')},
            { ARG_NULL , ARG_NULL , ARG_NULL , ARG_NULL }
        };

        int option_index = 0;
        c = getopt_long(argc, argv, _T("abc:d:f:"), long_options, &option_index);

        // Check for end of operation or error
        if (c == -1)
            break;

        // Handle options
        switch (c)
        {
        case 0:
            /* If this option set a flag, do nothing else now. */
            if (long_options[option_index].flag != 0)
                break;
            _tprintf (_T("option %s"), long_options[option_index].name);
            if (optarg)
                _tprintf (_T(" with arg %s"), optarg);
            _tprintf (_T("\n"));
            break;

        case _T('a'):
            _tprintf(_T("option -a\n"));
            break;

        case _T('b'):
            _tprintf(_T("option -b\n"));
            break;

        case _T('c'):
            _tprintf (_T("option -c with value `%s'\n"), optarg);
            break;

        case _T('d'):
            _tprintf (_T("option -d with value `%s'\n"), optarg);
            break;

        case _T('f'):
            _tprintf (_T("option -f with value `%s'\n"), optarg);
            break;

        case '?':
            /* getopt_long already printed an error message. */
            break;

        default:
            abort();
        }
    }

    if (verbose_flag)
        _tprintf (_T("verbose flag is set\n"));


    if (optind < argc)
    {
        _tprintf (_T("non-option ARGV-elements: "));
        while (optind < argc) _tprintf (_T("%s "), argv[optind++]);
        _tprintf (_T("\n"));
    }
    return 0;
}     

Using this Code with C++ Precompiled Headers

When using this code statically within a C++ project with precompiled headers, it is necessary to rename getopt.c to getopt.cpp in order to circumvent the following compiler error:

“C1853 - Precompiled header file is from a previous version of the compiler, 
or the precompiled header is C++ and you are using it from C (or vice versa).”

Additionally precompiled header file must be added as the first include of the getopt.c or getopt.cpp file. For example, if you are using "stdafx.h" as the precompiled header, the following would be expected:

// File comments removed
#include "stdafx.h"
#define _CRT_SECURE_NO_WARNINGS
#include <stdlib.h>
#include <stdio.h>
#include "getopt.h"

History

• 02/03/2011 - Initial release
• 02/20/2011 - Fixed L4 compiler warnings
• 07/05/2011 - Added no_argument, required_argument, optional_argument def
• 08/05/2011 - Fixed non-argument runtime bug which caused runtime exception
• 08/09/2011 - Added code to export functions for DLL and LIB
• 02/15/2012 - Fixed _GETOPT_THROW definition missing in implementation file

This article, along with any associated source code and files, is licensed under The GNU Lesser General Public License (LGPLv3)