Thread: problems with strcpy

I'm trying to copy a recieved char-array (cur) into cur2. Cur is a line read by fgets from user-input.

I need a copy because cur is later divided into words, but cur2 should hold the entire line. A simplified code-snippet:

Code:

#define MAX 20000
#define LINE 120
#define WORDS 20

void run (char cur[]) 
{
    char *param[MAX];
    char *temp[MAX];
    char cur2[WORDS];
    int s;

    cur[strlen(cur)-1] = '\0';
    strcpy(cur2, cur);
    temp[s] = cur2;
    s++;
}

int main (void)
{
  char *cur;
while (1) {
    printf("input >");
    fflush(stdout);
    cur = malloc(LINE);
    if (fgets(cur,LINE,stdin) == NULL) {
      free(cur);  
      break;
    }
    if (n>=MAX) {
      printf("buffer overflow..\n");  
      exit(0);
    }
    run(cur);
  }
  exit(0);
}

The idea is that temp[] should hold each input-line, but somehow every element is replaced by the input .

If input is:
> pwd
> ls -la
> h

then temp[0], temp[1], and temp[2] now contains 'h'. Any help would be appreciated!!

Your code doesn't compile without errors.

s is uninitialised in your run() function, so setting temp[s] = cur2 will yield undefined behaviour. Also, in main(), you are calling malloc() every time through the loop and only freeing the result when fgets() returns NULL (on end of file or error) => memory leak. The variable n in main() is not declared, so the code shouldn't compile. That's just on a quick look; I haven't dug any deeper.

Code:

void run (char cur[]) 
{
  char *param[MAX]; // this is like saying, 
                    // I want to have a pointer to a string
                    //  are you sure you know what you are doing?

  char *temp[MAX]; // see above
  char cur2[WORDS];
  int s; // uninitialized

  cur[strlen(cur)-1] = '\0';
  strcpy(cur2, cur); // maybe use strncpy? strncpy(cur2, cur, strlen(cur));
  temp[s] = cur2; 
  s++; // erh... what for?
}

Its only a snippet of a bigger system, pasting the whole code here would be too much... the code-snippet shouldnt compile... Thanks for the quick replies though. Strncpy did the trick! Thanks yxunomei

Thanks for all the help! It solved my errors