148349Scael.\" Copyright (c) 1991 The Regents of the University of California. 242104Sbostic.\" All rights reserved. 320290Smckusick.\" 4*50283Sbostic.\" This code is derived from software contributed to Berkeley by 5*50283Sbostic.\" the American National Standards Committee X3, on Information 6*50283Sbostic.\" Processing Systems. 7*50283Sbostic.\" 842104Sbostic.\" %sccs.include.redist.man% 942104Sbostic.\" 10*50283Sbostic.\" @(#)atof.3 6.4 (Berkeley) 06/29/91 1142104Sbostic.\" 1248349Scael.Dd 1348349Scael.Dt ATOF 3 1448349Scael.Os 1548349Scael.Sh NAME 1648349Scael.Nm atof 1748349Scael.Nd convert 1848349Scael.Tn ASCII 1948349Scaelstring to double 2048349Scael.Sh SYNOPSIS 2148349Scael.Fd #include <stdlib.h> 2248349Scael.Ft double 2348349Scael.Fn atof "const char *nptr" 2448349Scael.Sh DESCRIPTION 2542104SbosticThe 2648349Scael.Fn atof 2742104Sbosticfunction converts the initial portion of the string pointed to by 2848349Scael.Ar nptr 2942104Sbosticto 3048349Scael.Ar double 3142104Sbosticrepresentation. 3248349Scael.Pp 3342104SbosticIt is equivalent to: 3448349Scael.Bd -literal -offset indent 3542104Sbosticstrtod(nptr, (char **)NULL); 3648349Scael.Ed 3748349Scael.Sh SEE ALSO 3848349Scael.Xr atoi 3 , 3948349Scael.Xr atol 3 , 4048349Scael.Xr strtod 3 , 4148349Scael.Xr strtol 3 , 4248349Scael.Xr strtoul 3 4348349Scael.Sh STANDARDS 4448349ScaelThe 4548349Scael.Fn atof 4648349Scaelfunction conforms to 4748349Scael.St -ansiC . 4848349Scael.Sh BUGS 4942104SbosticThis manual page represents intent instead of actual practice. 5042104SbosticWhile it is intended that 5148349Scael.Fn atof 5242104Sbosticbe implemented using 5348349Scael.Xr strtod 3 , 5442104Sbosticthis has not yet happened. 5542104SbosticIn the current system, 5648349Scael.Fn atof 5748349Scaeltranslates a string in the following form to a double: a string of 5848349Scaelleading white space, possibly followed by a sign (``+'' or ``-''), 5948349Scaelfollowed by a digit string which may contain one decimal point (``.''), 6048349Scaelwhich may be followed by either of the exponent flags (``E'' or ``e''), 6148349Scaeland lastly, followed by a signed or unsigned integer. 62