写程序遇到的问题(一)

#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <unistd.h>
#include <glob.h>
//#include <string.h>
#define DELIMS   " \t\n"
static void prompt(void)
{
    printf("mysh-0.1$ ");
}
static int   parse(const  char* line,glob_t *globres)
{
    printf("line:%s\n",line);
    char *tok;
    int i =0;
    while(1)
    {
         tok =   strsep(&line,DELIMS);
         if( tok == NULL)
             break;
//             printf("tok:%s:len:%ld\n",tok,strlen(tok));
         if( tok[0] == '\0')
             continue;

         glob(tok,GLOB_NOCHECK|GLOB_APPEND * i,NULL,globres);
            i = 1;
    }
    return 1;
}
int main(int argc,char ** argv)
{
    char * linebuf = NULL;
    size_t linebuf_size = 0;
    glob_t globres;
    while(1)
    {
        prompt();

        if (getline(&linebuf,&linebuf_size,stdin)<0)
            break;
        parse(linebuf,&globres);
        if(0)
        {
        }
        else
        {

            pid_t pid = fork();
            if( pid <0)
            {
                perror("fork()");
               
            }
            if( pid == 0)
            {

                execvp(globres.gl_pathv[0],globres.gl_pathv);
                perror("execvp()");
                exit(0);

            }

        }
    }

    exit(0);
}

 如果不添加#include<string.h> 虽然编译通过但是会在 if( tok[0] == '\0') 提示段错误