src/stdlib/atol.c

   1 #include <stdlib.h>
   2 #include <ctype.h>
   3
   4 long atol(const char *s)
   5 {
   6         long n=0;
   7         int neg=0;
   8         while (isspace(*s)) s++;
   9         switch (*s) {
  10         case '-': neg=1;
  11         case '+': s++;
  12         }
  13         /* Compute n as a negative number to avoid overflow on LONG_MIN */
  14         while (isdigit(*s))
  15                 n = 10*n - (*s++ - '0');
  16         return neg ? n : -n;
  17 }