Create salted MD5 passwort for /etc/shadow

Hi

I am trying to generate a salted md5 hash in C with the propper format "$1$salt$hash" for the /etc/shadow file.

I am not quite sure if $1$ should be part of the salt or not? Right now I use the following code to generate a salt and create the passwort using crypt()

char salt[9];
  char full[50];

  int i = 0;
  static char *choices = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
                         "0123456789./";

  for(i = 0; i<8; i++)
  {
    salt[i] = choices[random_in_range(0, strlen(choices) - 1)];
  }
  salt[8] = 0;

  sprintf(full,"$1$%s",salt);

  /* Loop thru passwd file */
  char pw[100];

  sprintf(pw,"$1$%s$%s",salt,crypt(password, full));

Any hint would be great!