NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | CONFORMING TO | NOTES | SEE ALSO | COLOPHON
ATOI(3) Linux Programmer's Manual ATOI(3)
atoi, atol, atoll, atoq - convert a string to an integer
#include <stdlib.h>
int atoi(const char *nptr);
long atol(const char *nptr);
long long atoll(const char *nptr);
long long atoq(const char *nptr);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
atoll(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 ||
_ISOC99_SOURCE; or cc -std=c99
The atoi() function converts the initial portion of the string pointed to by
nptr to int. The behavior is the same as
strtol(nptr, (char **) NULL, 10);
except that atoi() does not detect errors.
The atol() and atoll() functions behave the same as atoi(), except that they
convert the initial portion of the string to their return type of long or long
long. atoq() is an obsolete name for atoll().
The converted value.
SVr4, POSIX.1-2001, 4.3BSD, C99. C89 and POSIX.1-1996 include the functions
atoi() and atol() only. atoq() is a GNU extension.
The non-standard atoq() function is not present in libc 4.6.27 or glibc 2, but
is present in libc5 and libc 4.7 (though only as an inline function in
<stdlib.h> until libc 5.4.44). The atoll() function is present in glibc 2
since version 2.0.2, but not in libc4 or libc5.
atof(3), strtod(3), strtol(3), strtoul(3)
This page is part of release 3.23 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be found
at http://www.kernel.org/doc/man-pages/.
GNU 2007-07-26 ATOI(3)