Manual Pages  — ATOI

atoi – convert ASCII string to integer

LIBRARY SYNOPSIS DESCRIPTION ERRORS SEE ALSO STANDARDS HISTORY

Standard C Library (libc, -lc)

#include <stdlib.h>

int
atoi(const char *nptr);

The atoi() function converts the initial portion of the string pointed to by nptr to int representation.

It is equivalent to:

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

The atoi() function has been deprecated by strtol() and should not be used in new code.

The function atoi() need not affect the value of errno on an error.

The atoi() function conforms to IEEE Std 1003.1-90 ("POSIX.1"), ISO/IEC 9899:1990 ("ISO C90"), and ISO/IEC 9899:1999 ("ISO C99").

The atoi() function appeared in AT&T v1 .