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[thirdparty/man-pages.git] / man3 / atoi.3

.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
.\"
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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  2012-08-03 "GNU" "Linux Programmer's Manual"
.SH NAME
atoi, atol, atoll, atoq \- convert a string to an integer
.SH SYNOPSIS
.nf
.B #include <stdlib.h>
.sp
.BI "int atoi(const char *" nptr );
.br
.BI "long atol(const char *" nptr );
.br
.BI "long long atoll(const char *" nptr );
.br
.BI "long long atoq(const char *" nptr );
.fi
.sp
.in -4n
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.in
.sp
.ad l
.BR atoll ():
.RS 4
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE\ >=\ 200112L;
.br
or
.I cc\ -std=c99
.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
.sp
.in +4n
strtol(nptr, NULL, 10);
.in
.sp
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.
.BR atoq ()
is an obsolete name for
.BR atoll ().
.SH RETURN VALUE
The converted value.
.SH CONFORMING TO
SVr4, POSIX.1-2001, 4.3BSD, C99.
C89 and
POSIX.1-1996 include the functions
.BR atoi ()
and
.BR atol ()
only.
.BR atoq ()
is a GNU extension.
.SH NOTES
The nonstandard
.BR 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 \fI<stdlib.h>\fP until libc 5.4.44).
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)