NAME
atoi —
convert ASCII string to
integer
SYNOPSIS
#include
<stdlib.h>
int
atoi(const
char *nptr);
DESCRIPTION
The
atoi()
function converts the initial portion of the string pointed to by
nptr to integer
representation.
It is equivalent to:
(int)strtol(nptr, (char **)NULL, 10);
SEE ALSO
atof(3), atol(3), strtod(3), strtol(3), strtonum(3), strtoul(3)
STANDARDS
The atoi() function conforms to
ANSI X3.159-1989
(“ANSI C89”).
HISTORY
An atoi() function first appeared in
Version 1 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) and
strtoul(3) can alleviate these problems, but
strtonum(3) can be used to convert numbers from strings much more
safely and easily.