I often use parts of GPL code in my own software. I've written the following function to minimize code changes wnen porting apps. It is enough to replace "main" function with "XXXX_main" and prepare argc/argc with my CommandLineToArgvAEx() if the application doesn't expect STDIN. Since argv[0] should contain path to executable we have to either prepend path to commangline or just reserve (and keep empty) argv[0].

This implementation allows parsing commandline-like strings in arbitrary encodings.

Find the sources of CommandLineToArgvAEx() and related functions below:

cmdl2argv.c

#include 

char *utf16_to_char(LPWSTR str, int cp, int *plength)
{
	char *p = NULL;
	int cc;
	// get length (cc) of the new multibyte string excluding the \0 terminator first
	if (plength)
		*plength = 0;
	if ((cc = WideCharToMultiByte(cp, 0, str, -1, NULL, 0, 0, 0) - 1) > 0)
	{	// convert
		if (NULL != ( p = (char *)LocalAlloc(LMEM_FIXED, (cc + 1) * sizeof(char)))) {
			WideCharToMultiByte(cp, 0, str, -1, p, cc + 1, 0, 0);
			if (plength)
				*plength = cc;
		}
	}
	return p;
}

wchar_t *char_to_utf16(const char *str, int cp, int *plength)
{
	wchar_t *p=NULL;
	int cc = 0;
	if (plength)
		*plength = 0;
	// get length (cc) of the new widechar excluding the \0 terminator first
	if ((cc = MultiByteToWideChar(cp, 0, str, -1, NULL, 0) - 1) > 0) {	// convert
		if (NULL != (p = (wchar_t *)LocalAlloc(LMEM_FIXED, (cc+1)*sizeof(wchar_t)))) {
			MultiByteToWideChar(cp, 0, str, -1, p, cc + 1);           
			if (plength)
				*plength = cc;
		}
	}
	return p;
}

char **CommandLineToArgvAEx(char *cmdline, int *p_my_args, int reserv, int src_cp, int dst_cp )
{
	char **argv = NULL, **scattered_argv;
	*p_my_args = 0;
	LPWSTR *args;
	size_t count_of_mem = 0;
	int cc;
	wchar_t *s = char_to_utf16(cmdline, src_cp, NULL);
	if (NULL != s) {
		if (NULL != (args = CommandLineToArgvW(s, p_my_args))) {
			LocalFree(s);
			if (NULL != (scattered_argv = (char **)LocalAlloc(LMEM_FIXED, *p_my_args * sizeof(char *)))) {
				for (int i = 0; i < *p_my_args; ++i)
					if (NULL != (scattered_argv[i] = utf16_to_char(args[i], dst_cp, &cc)))
						count_of_mem += (cc + 1)*sizeof(char);
				if (count_of_mem) {
					count_of_mem += (*p_my_args + reserv) * sizeof(char *);
					if (NULL != (argv = (char **)LocalAlloc(LMEM_FIXED|LMEM_ZEROINIT, count_of_mem))) {
						cc = (*p_my_args + reserv) * sizeof(char *);
						for (int i = reserv; i < *p_my_args + reserv; ++i) {
							if (NULL != scattered_argv[i - reserv]) {
								argv[i] = (char *)argv + cc;
								strcpy(argv[i], scattered_argv[i - reserv]);
								cc += (int)strlen(argv[i]) + 1;
								LocalFree(scattered_argv[i - reserv]);
							}
						}
					}
				}
				LocalFree(scattered_argv);
			}
			LocalFree(args);
		}	
	}
	return argv;
}

char **CommandLineToArgvA(char *cmdline, int *p_my_args)
{
	return CommandLineToArgvAEx(cmdline, p_my_args, 0, GetOEMCP(), GetACP());
}

char **CommandLineToArgvA_Res(char *cmdline, int *p_my_args, int n_reserv)
{
	return CommandLineToArgvAEx(cmdline, p_my_args, n_reserv, GetOEMCP(), GetACP());
}

void cleanup_cmdline(char **argv)
{
	LocalFree(argv);
}

cmdl2argv.h

#ifndef _CMDL2ARGV_H
#define _CMDL2ARGV_H
#ifdef __cplusplus
extern "C" {
#endif
    // "Standard"  behaviour
	char **CommandLineToArgvA(char *cmdline, int *pargc);
	// First  n_reserv argv's may be setlled up by caller 
	char **CommandLineToArgvA_Res(char *cmdline, int *pargc, int n_reserv);
	// First  n_reserv argv's may be setlled up by caller  + code page conversion
	char **CommandLineToArgvAEx(char *cmdline, int *pargc, int n_reserv, int srcCP, int dstCP);
#ifndef _INC_WINDOWS
	void cleanup_cmdline(char **argv);
#else 
    #define  cleanup_cmdline(argv)  LocalFree(argv)
#endif
#ifdef __cplusplus
}
#endif

#endif

See also:

• CommandLineToArgvA()/CommandLineToArgvW()