G:/ScriptBasic/source/getopt.c

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/***************************************************************************\
**                                                                         **
**   Function name: getopt()                                               **
**   Author:        Henry Spencer, UofT                                    **
**   Coding date:   84/04/28                                               **
**                                                                         **
**   Description:                                                          **
**                                                                         **
**   Parses argv[] for arguments.                                          **
**   Works with Whitesmith's C compiler.                                   **
**                                                                         **
**   Inputs   - The number of arguments                                    **
**            - The base address of the array of arguments                 **
**            - A string listing the valid options (':' indicates an       **
**              argument to the preceding option is required, a ';'        **
**              indicates an argument to the preceding option is optional) **
**                                                                         **
**   Outputs  - Returns the next option character,                         **
**              '?' for non '-' arguments                                  **
**              or ':' when there is no more arguments.                    **
**                                                                         **
**   Side Effects + The argument to an option is pointed to by 'optarg'    **
**                                                                         **
*****************************************************************************
**                                                                         **
**   REVISION HISTORY:                                                     **
**                                                                         **
**     DATE           NAME                        DESCRIPTION              **
**   YY/MM/DD  ------------------   ------------------------------------   **
**   88/10/20  Janick Bergeron      Returns '?' on unamed arguments        **
**                                  returns '!' on unknown options         **
**                                  and 'EOF' only when exhausted.         **
**   88/11/18  Janick Bergeron      Return ':' when no more arguments      **
**   89/08/11  Janick Bergeron      Optional optarg when ';' in optstring  **
**   99/05/22  Peter Verhas         optarg is argument to be thread safe   **
**   99/08/28  Peter Verhas         optind becomes argument                **
**   02/11/28  Nigel Hathaway       MacOS variation                        **
**                                                                         **
\***************************************************************************/
#include <stdio.h>
#ifdef VMS
#define index  strchr
#endif
#ifdef WIN32
#define index  strchr
#endif
#ifdef __MACOS__
#define index  strchr
#endif

/*FUNCTION*/
char getoptt(int argc, 
            char **argv,
            char *optstring,
            char **optarg,
            int *poptind
  ){
#define optind (*poptind)
        register int c;
        register char *place;
        extern char *index();
        static char *scan = NULL;

        *optarg = NULL;

        if (scan == NULL || *scan == '\0') {

                if (optind == 0)
                        optind++;
                if (optind >= argc)
                        return ':';

                *optarg = place = argv[optind++];
                if (place[0] != '-' || place[1] == '\0')
                        return '?';
                if (place[1] == '-' && place[2] == '\0')
                        return '?';
                scan = place + 1;
        }

        c = *scan++;
        place = index(optstring, c);
        if (place == NULL || c == ':' || c == ';') {
                scan = NULL;
                return '!';
        }
        if (*++place == ':') {

                if (*scan != '\0') {

                        *optarg = scan;
                        scan = NULL;

                }
                else {

                        if (optind >= argc) {
                                return '!';
                        }
                        *optarg = argv[optind];
                        optind++;
                }
        }
        else if (*place == ';') {

                if (*scan != '\0') {

                        *optarg = scan;
                        scan = NULL;

                }
                else {

                        if (optind >= argc || *argv[optind] == '-')
                                *optarg = NULL;
                        else {
                                *optarg = argv[optind];
                                optind++;
                        }
                }
        }
        return c;
}

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