man3/atoi.3

   1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
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  23 .\" References consulted:
  24 .\"     Linux libc source code
  25 .\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
  26 .\"     386BSD man pages
  27 .\" Modified Mon Mar 29 22:39:41 1993, David Metcalfe
  28 .\" Modified Sat Jul 24 21:38:42 1993, Rik Faith (faith@cs.unc.edu)
  29 .\" Modified Sun Dec 17 18:35:06 2000, Joseph S. Myers
  30 .\"
  31 .TH ATOI 3  2000-12-17 "GNU" "Linux Programmer's Manual"
  32 .SH NAME
  33 atoi, atol, atoll, atoq \- convert a string to an integer
  34 .SH SYNOPSIS
  35 .nf
  36 .B #include <stdlib.h>
  37 .sp
  38 .BI "int atoi(const char *" nptr );
  39 .br
  40 .BI "long atol(const char *" nptr );
  41 .br
  42 .BI "long long atoll(const char *" nptr );
  43 .br
  44 .BI "long long atoq(const char *" nptr );
  45 .fi
  46 .SH DESCRIPTION
  47 The \fBatoi\fP() function converts the initial portion of the string
  48 pointed to by \fInptr\fP to
  49 .IR int .
  50 The behaviour is the same as
  51 .sp
  52 .RS
  53 .B strtol(nptr, (char **) NULL, 10);
  54 .RE
  55 .sp
  56 except that \fBatoi\fP() does not detect errors.
  57 .PP
  58 The \fBatol\fP() and \fBatoll\fP() functions behave the same as
  59 \fBatoi\fR(), except that they convert the initial portion of the
  60 string to their return type of \fIlong\fP or \fIlong long\fP.
  61 \fBatoq\fP() is an obsolete name for \fBatoll\fP().
  62 .SH "RETURN VALUE"
  63 The converted value.
  64 .SH "CONFORMING TO"
  65 SVr4, POSIX.1-2001, 4.3BSD, C99.
  66 C89 and
  67 POSIX.1-1996 include the functions \fBatoi\fP() and \fBatol\fP() only.
  68 .BR atoq (3)
  69 is a GNU extension.
  70 .SH NOTES
  71 The non-standard \fBatoq\fP() function is not present in libc 4.6.27
  72 or glibc 2, but is present in libc5 and libc 4.7 (though only as an
  73 inline function in \fB<stdlib.h>\fP until libc 5.4.44).  The
  74 \fBatoll\fP() function is present in glibc 2 since version 2.0.2, but
  75 not in libc4 or libc5.
  76 .SH "SEE ALSO"
  77 .BR atof (3),
  78 .BR strtod (3),
  79 .BR strtol (3),
  80 .BR strtoul (3)