How to properly use a C function?

This is a discussion on How to properly use a C function? within the C Programming forums, part of the General Programming Boards category; Below I posted a small piece of my code. I'm not familiar with using this C function that's highlighted in ...

  1. #1
    Registered User
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    Sep 2007
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    How to properly use a C function?

    Below I posted a small piece of my code. I'm not familiar with using this C function that's highlighted in red and my program generates the following when executed:

    "10 [main] a.out 4488 _cygtls::handle_exceptions: Error while dumping state (probably corrupted stack)"

    As of right now i'm not passing the command to the function, only the arguments after it. Any help would be great. Thanks in advance.

    Code:
    char *string = "ls *.c";
    char *token;
    int count = 0;
    boolean FIRSTGLOB = TRUE;  //ignore boolean, already been type def'ed
    int status = 0;
    glob_t globbuf;
    
    token = strtok( input, " " );
    command = token; 
    
    while( token != NULL ) //process arguments after command ( i.e. "*.c" )
    {
    		token = strtok( NULL, " " );
    		arguments[ count ] = token;
    		count++;
    }
    
    //in this case count will = 1, and the only argument was "*.c", so arguments[] only contains
    // "*.c"  (should it also contain "ls"?)
    
    for( i=0; i<count; i++ ) //call the glob function for the number of wildcard arguments found
    {
    	if( !FIRSTGLOB ) //more than one wildcard argument was found
    		glob( arguments[i], GLOB_DOOFFS | GLOB_APPEND, NULL, &globbuf );
    	else //only a single wildcard argument
    	{
    	       glob( arguments[i], GLOB_DOOFFS, NULL, &globbuf );
    	       FIRSTGLOB = FALSE; //no longer the first "glob", could be more wildcards
    	}
    
    }
    
       status = execvp( cmd, &globbuf.gl_pathv[0] );

  2. #2
    a_capitalist_story
    Join Date
    Dec 2007
    Posts
    2,639
    This works:
    Code:
    #include <stdio.h>
    #include <glob.h>
    #include <stdlib.h>
    #include <string.h>
    
    #define MAX_ARGS 20
    
    int main()
    {
        char *cmd = strdup("ls *.php *.sh *.yo");
        char *arguments[MAX_ARGS] = { 0 };
        char *token = NULL; 
        char *command = strtok(cmd, " ");
        int count = 0;
        while (NULL != (token = strtok(NULL, " ")) && count < MAX_ARGS)
        {
            arguments[count++] = token;
        }
    
        glob_t globbuf = { 0 };
        int i = 0;
        int rc = 0;
        for (; i < count ; ++i)
        {
            if (0 != (rc = glob(arguments[i], GLOB_DOOFFS | GLOB_APPEND, 
                                NULL, &globbuf)))
            {
                if (GLOB_NOMATCH == rc)
                    continue;
                fprintf(stderr, "glob failed: &#37;d\n", rc);
                free(cmd);
                return -1;
            }
        }
        for (i = 0; i < globbuf.gl_pathc; ++i)
        {
            printf("Argument %d: %s\n", i, globbuf.gl_pathv[i]);
        }
        globfree(&globbuf);
        free(cmd);
        return 0;
    }
    Quote Originally Posted by Output
    neon:~ me$ ./globtest
    Argument 0: qs.php
    Argument 1: sbtest.php
    Argument 2: test.php
    Argument 3: blah.sh
    Argument 4: yoohoo.sh
    Argument 5: p.sh
    neon:~ me$
    Last edited by rags_to_riches; 05-29-2008 at 04:06 PM. Reason: Missing newline

  3. #3
    Registered User
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    119
    I'm not sure how to apply that to what i'm trying to do. I'm trying to allow make the command "ls *.c" display all the C files in the current directory. Looking at your code doesn't really help me understand what I did wrong or how to fix it. But don't worry about it, I figured out what I was doing wrong. I now have a general solution to allow all and any types of globbing via input. Thanks anyways.
    Last edited by John_L; 05-29-2008 at 04:28 PM.

  4. #4
    C++まいる!Cをこわせ! Elysia's Avatar
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    Posts
    22,169
    First and foremost, string literals should be const char, not char.
    const char *string = "ls *.c";
    Second, I don't see where you define arguments. Most likely, your "arguments" variable isn't big enough to hold the data, but of course I can't be sure.

    You are overwriting data you shouldn't somewhere. That's why you get an error.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.
    For information on how to enable C++11 on your compiler, look here.
    よく聞くがいい!私は天才だからね! ^_^

  5. #5
    Kernel hacker
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    Location
    Farncombe, Surrey, England
    Posts
    15,677
    One difference I see is that your globbuf isn't initialized. I don't KNOW if that's of any importance tho'.

    --
    Mats
    Compilers can produce warnings - make the compiler programmers happy: Use them!
    Please don't PM me for help - and no, I don't do help over instant messengers.

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