windows mingw asterisk '*' passing by argv

Question

I wrote a code below

#include<stdio.h>

int main(int argc, char *argv[]) {
    char cmd[50]="dir";
    if (argc == 2) {
        sprintf(cmd,"dir %s",argv[1]);
    }
    if (argc == 3) {
        sprintf(cmd,"dir %s %s", argv[1], argv[2]);
    }
    printf("%s\n",cmd);
    system(cmd);
    return 0;
}

when I executed like below

I think can't pass '*' by *argv[]

How can I pass something like "*.c" ?

update

code

#include<stdio.h>

int main(int argc, char *argv[]) {
    char cmd[50]="dir";
    if (argc == 2) {
        sprintf(cmd,"dir %s",argv[1]);
    }
    if (argc == 3) {
        sprintf(cmd,"dir %s %s", argv[1], argv[2]);
    }
    if (argc > 3) {
        sprintf(cmd,"dir %s %s", argv[1], argv[2]);
    }
    printf("%s\n",cmd);
    system(cmd);
    return 0;
}

changing is below

what..... @.@ ?

Updated code again

#include<stdio.h>
#include<string.h>

int main(int argc, char *argv[]) {
    int i;
    char sp[2]=" ", cmd[250]="dir";
    if (argc > 1) {
        sprintf(cmd,"dir /d ");
        for (i =1 ; i < argc; i ++)  {
            strcat(cmd,sp);
            strcat(cmd,argv[i]);
        }
    }
    printf("%s\n",cmd);
    system(cmd);
    return 0;
}

see what happen when I executed

kind of ugly.... any decent idea?

Answer 1

I'm afraid the accepted answer is not correct as the edit courteously admits. What is happening here is that globbing behaviour is provided in the C runtime but the default behaviour differs between compilers.

Yes, it's a major pain if you do not know what is happening. Worse the globbing does not occur if the glob does not match any files. I was pretty surprised myself.

Under Visual Studio, by default, wildcards are not expanded in command-line arguments. You can enable this feature by linking with setargv.obj or wsetargv.obj:

cl example.c /link setargv.obj

Under MinGW, by default, wildcards are expanded in command line arguments. To prevent this you can link with CRT_noglob.o or, much more easily, add the global variable:

int _CRT_glob = 0; 

in your own source in the file which defines main() or WinMain().

Answer 2

This issue is not related to the C runtime, but to the shell behaviour. If you use Windows CMD.EXE, the * is passed unchanged to the programs, whereas if you use Cygwin's bash, the shell expands * to the list of files and passes this expansion as individual arguments to your program. You can prevent this expansion by quoting the wildcards with "*" or '*'.

Note that you should not use sprintf, but snprintf to avoid buffer overflows. If you link to the non standard Microsoft C library, you may need to use _snprintf instead.

EDIT: CMD.EXE does not seem to expand wildcards, but the C runtime you link your program with might do it at startup. See this question: Gnuwin32 find.exe expands wildcard before performing search

The solution is to quote the argument.