xwd: ./dsimple.c:277:17: warning: macro expands to multiple statements [-Wmultistatement-macros]

[MEERSMAN Koen (EXT)]

Hi

When compiling dsimple.c with -Wall we get warning:

        ./dsimple.c: In function 'Select_Window_Args':
        ./dsimple.c:277:17: warning: macro expands to multiple statements [-Wmultistatement-macros]
         #define COPYOPT nargv++[0]=OPTION; nargc++
                         ^~~~~
        ./dsimple.c:283:27: note: in expansion of macro 'COPYOPT'
                                   COPYOPT;
                                   ^~~~~~~
        ./dsimple.c:282:25: note: some parts of macro expansion are not guarded by this 'while'         clause
                                 while (NXTOPTP)
                                         ^~~~~

Question I have is what should the code do:

-- original code:

        #define COPYOPT nargv++[0]=OPTION; nargc++

            while (NXTOPTP) {
                        if (!strcmp(OPTION, "-")) {
                                COPYOPT;
                                while (NXTOPTP)
                                  COPYOPT;
                                break;
                        }

-- fixed code
        #define COPYOPT nargv++[0]=OPTION; nargc++

            while (NXTOPTP) {
                        if (!strcmp(OPTION, "-")) {
                                COPYOPT;
>                               while (NXTOPTP) {
>                                 nargv++[0]=OPTION
>                           }
                                break;
                        }

-- now it does: (what looks wrong to me)

        #define COPYOPT nargv++[0]=OPTION; nargc++

            while (NXTOPTP) {
                        if (!strcmp(OPTION, "-")) {
                                COPYOPT;
>                               while (NXTOPTP) {
>                                 COPYOPT;
>                           }
>                           nargc++
                                break;
                        }

Can't find any usage of Select_Window_Args so I can't test.



Tnx,

Koen


----


/*
 * Select_Window_Args: a rountine to provide a common interface for
 *                     applications that need to allow the user to select one
 *                     window on the screen for special consideration.
 *                     This routine implements the following command line
 *                     arguments:
 *
 *                       -root            Selects the root window.
 *                       -id <id>         Selects window with id <id>. <id> may
 *                                        be either in decimal or hex.
 *                       -name <name>     Selects the window with name <name>.
 *
 *                     Call as Select_Window_Args(&argc, argv) in main before
 *                     parsing any of your program's command line arguments.
 *                     Select_Window_Args will remove its arguments so that
 *                     your program does not have to worry about them.
 *                     The window returned is the window selected or 0 if
 *                     none of the above arguments was present.  If 0 is
 *                     returned, Select_Window should probably be called after
 *                     all command line arguments, and other setup is done.
 *                     For examples of usage, see xwininfo, xwd, or xprop.
 */
Window Select_Window_Args(
                          int *rargc,
                          char **argv)
#define ARGC (*rargc)
{
        int nargc=1;
        int argc;
        char **nargv;
        Window w=0;

        nargv = argv+1; argc = ARGC;
#define OPTION argv[0]
#define NXTOPTP ++argv, --argc>0
#define NXTOPT if (++argv, --argc==0) usage()
#define COPYOPT nargv++[0]=OPTION; nargc++

        while (NXTOPTP) {
                if (!strcmp(OPTION, "-")) {
                        COPYOPT;
                        while (NXTOPTP)
                          COPYOPT;
                        break;
                }
                if (!strcmp(OPTION, "-root")) {
                        w=RootWindow(dpy, screen);
                        continue;
                }
                if (!strcmp(OPTION, "-name")) {
                        NXTOPT;
                        w = Window_With_Name(dpy, RootWindow(dpy, screen),
                                             OPTION);
                        if (!w)
                          Fatal_Error("No window with name %s exists!",OPTION);
                        continue;
                }
                if (!strcmp(OPTION, "-id")) {
                        NXTOPT;
                        w=0;
                        sscanf(OPTION, "0x%lx", &w);
                        if (!w)
                          sscanf(OPTION, "%lu", &w);
                        if (!w)
                          Fatal_Error("Invalid window id format: %s.", OPTION);
                        continue;
                }
                COPYOPT;
        }
        ARGC = nargc;

        return(w);
}

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