ATOI(3)

NAME
atoi, atoi_l - convert ASCII string to integer

SYNOPSIS
#include <stdlib.h>
int
atoi(const char *nptr);
#include <xlocale.h>
int
atoi_l(const char *nptr, locale_t loc);

DESCRIPTION
The atoi() and atoi_l() function converts the initial portion of the string pointed to by nptr to integer representation. The atoi() function uses the current locale while atoi_l() uses the locale given as parameter, see xlocale(3).

It is equivalent to:

    (int)strtol(nptr, (char **)NULL, 10);

SEE ALSO
atof(3), atol(3), strtod(3), strtol(3), strtonum(3), strtoul(3) xlocale(3).

STANDARDS
The atoi() function conforms to ansiC. The atoi_l() function is a Darwin extension.

HISTORY
An atoi() function first appeared in AT&T UNIX.

CAVEATS
atoi does no overflow checking, handles unsigned numbers poorly, and handles strings containing trailing extra characters (like “123abc”) poorly. Careful use of strtol(3), strtol_l(3), strtoul(3) and strtoul_l(3) can alleviate these problems, but strtonum(3) can be used to convert numbers from strings much more safely and easily.