read from argv[0]

Question

Hi i have a simple C question .. :

int main(int argc,char *argv[])
{
  char *text;
  int textLen,repNum;

  text = stream2string(stdin,&textLen);
  //....text = argv[0] doesnt work :(

so how can i read from argv[0]? I use netbeans .. and everytime i have to type in stdin.. when i use argv then the programm will execute without my input.

UPDATE :

Everytime , i start the programm(netbeans green button) .. i have to Type an Example String ! I am lazy.. the string is always the same : ABAABAABBBA So ..i will take the first argument instead of stdin . But argv[1] doesn't work either .. here is :

stream2string :

char *stream2string (FILE *fptr, int *n)
{
  static char *s;

  *n = 0;
  ALLOC(s,char,2);
  s[*n] = getc(fptr);

  while(s[*n]!=EOF && s[*n]!='\0' && s[*n]!='\n') {
   REALLOC(s,char,++*n+2);
  s[*n] = getc(fptr);
   }
  s[*n] = '\0';
  return(s);
} /* stream2string() */

I think .. setting textLen is also important. Can anybody help ?

Answer 1

Try to use argv[1] instead to read the first argument. argv[0] returns the name of the executable that was called (or the name of the link to the executable on Unix/Linux systems).

Answer 2

This sounds like you haven't set the program arguments for when it is run in the IDE. This is a NetBeans issue - nothing to do with C.

Answer 3

argv[0] is the name of your executable; I don't think you want to read from that! Rather, I think you want to open argv[1] (the filename given as the first argument to your program on the commandline) and read that:

int main(int argc,char *argv[])
{
  char *text;
  int textLen,repNum;
  FILE *theinput;

  if (argc < 2) {
    /* no argument */
    /* give error message and exit */
    fprintf(stderr, "Must pass an argument!\n");
    exit(1);
  }

  theinput = fopen(argv[1], "r");

  if (!theinput) {
    /* Argument is non-existing file */
    /* give error message and exit */
    fprintf(stderr, "Can't read %s\n", argv[1]);
    exit(1);
  }

  text = stream2string(theinput, &textLen);

  fclose(theinput);

etc. (Of course you can and should provide more detailed and helpful error messages, etc, etc, but I'm trying to focus on the key points that you appeared to be missing).

Edit: ah well, focus seems out of fashion, judging from the comments, so I just edited to provide minimally acceptable error messages.