ref: bb3a3db29db8b3c84e54aa820fe3f37b2b979794
dir: /lib/c/atol.c/
#include <ctype.h> #include <stdlib.h> #undef atol long atol(const char *s) { int sign = -1; long n; while (isspace(*s)) ++s; switch (*s) { case '-': sign = 1; case '+': ++s; } /* Compute n as a negative number to avoid overflow on LONG_MIN */ for (n = 0; isdigit(*s); ++s) n = 10*n - (*s - '0'); return sign * n; }