.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
.\"
.\" %%%LICENSE_START(VERBATIM)
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.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
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.\"
.\" References consulted:
.\"     Linux libc source code
.\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
.\"     386BSD man pages
.\" Modified Mon Mar 29 22:39:41 1993, David Metcalfe
.\" Modified Sat Jul 24 21:38:42 1993, Rik Faith (faith@cs.unc.edu)
.\" Modified Sun Dec 17 18:35:06 2000, Joseph S. Myers
.\"
.TH ATOI 3  2016-03-15 "GNU" "Linux Programmer's Manual"
.SH NAME
atoi, atol, atoll \- convert a string to an integer
.SH SYNOPSIS
.nf
.B #include <stdlib.h>
.PP
.BI "int atoi(const char *" nptr );
.BI "long atol(const char *" nptr );
.BI "long long atoll(const char *" nptr );
.fi
.PP
.in -4n
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.in
.PP
.ad l
.BR atoll ():
.RS 4
__ISOC99_SOURCE ||
    || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
.RE
.ad
.SH DESCRIPTION
The
.BR atoi ()
function converts the initial portion of the string
pointed to by \fInptr\fP to
.IR int .
The behavior is the same as
.PP
.in +4n
.EX
strtol(nptr, NULL, 10);
.EE
.in
.PP
except that
.BR atoi ()
does not detect errors.
.PP
The
.BR atol ()
and
.BR atoll ()
functions behave the same as
.BR atoi (),
except that they convert the initial portion of the
string to their return type of \fIlong\fP or \fIlong long\fP.
.SH RETURN VALUE
The converted value.
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lbw23 lb lb
l l l.
Interface	Attribute	Value
T{
.BR atoi (),
.BR atol (),
.BR atoll ()
T}	Thread safety	MT-Safe locale
.TE
.SH CONFORMING TO
POSIX.1-2001, POSIX.1-2008, C99, SVr4, 4.3BSD.
C89 and
POSIX.1-1996 include the functions
.BR atoi ()
and
.BR atol ()
only.
.SH NOTES
Linux libc provided
.BR atoq ()
as an obsolete name for
.BR atoll ();
.BR atoq ()
is not provided by glibc.
.\" The
.\" .BR atoll ()
.\" function is present in glibc 2 since version 2.0.2, but
.\" not in libc4 or libc5.
.SH SEE ALSO
.BR atof (3),
.BR strtod (3),
.BR strtol (3),
.BR strtoul (3)
.SH COLOPHON
This page is part of release 4.15 of the Linux
.I man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
\%https://www.kernel.org/doc/man\-pages/.
