1.\" Copyright (c) 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the American National Standards Committee X3, on Information 6.\" Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. All advertising materials mentioning features or use of this software 17.\" must display the following acknowledgement: 18.\" This product includes software developed by the University of 19.\" California, Berkeley and its contributors. 20.\" 4. Neither the name of the University nor the names of its contributors 21.\" may be used to endorse or promote products derived from this software 22.\" without specific prior written permission. 23.\" 24.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34.\" SUCH DAMAGE. 35.\" 36.\" @(#)strtod.3 8.1 (Berkeley) 6/4/93 37.\" $FreeBSD$ 38.\" 39.Dd June 4, 1993 40.Dt STRTOD 3 41.Os 42.Sh NAME 43.Nm strtod 44.Nd convert 45.Tn ASCII 46string to double 47.Sh LIBRARY 48.Lb libc 49.Sh SYNOPSIS 50.In stdlib.h 51.Ft double 52.Fn strtod "const char * restrict nptr" "char ** restrict endptr" 53.Sh DESCRIPTION 54The 55.Fn strtod 56function converts the initial portion of the string 57pointed to by 58.Fa nptr 59to 60.Em double 61representation. 62.Pp 63The expected form of the string is an optional plus (``+'') or minus 64sign (``\-'') followed by a sequence of digits optionally containing 65a decimal-point character, optionally followed by an exponent. 66An exponent consists of an ``E'' or ``e'', followed by an optional plus 67or minus sign, followed by a sequence of digits. 68.Pp 69Leading white-space characters in the string (as defined by the 70.Xr isspace 3 71function) are skipped. 72The decimal point 73character is defined in the program's locale (category 74.Dv LC_NUMERIC ) . 75.Sh RETURN VALUES 76The 77.Fn strtod 78function returns the converted value, if any. 79.Pp 80If 81.Fa endptr 82is not 83.Dv NULL , 84a pointer to the character after the last character used 85in the conversion is stored in the location referenced by 86.Fa endptr . 87.Pp 88If no conversion is performed, zero is returned and the value of 89.Fa nptr 90is stored in the location referenced by 91.Fa endptr . 92.Pp 93If the correct value would cause overflow, plus or minus 94.Dv HUGE_VAL 95is returned (according to the sign of the value), and 96.Er ERANGE 97is stored in 98.Va errno . 99If the correct value would cause underflow, zero is 100returned and 101.Er ERANGE 102is stored in 103.Va errno . 104.Sh ERRORS 105.Bl -tag -width Er 106.It Bq Er ERANGE 107Overflow or underflow occurred. 108.El 109.Sh SEE ALSO 110.Xr atof 3 , 111.Xr atoi 3 , 112.Xr atol 3 , 113.Xr strtol 3 , 114.Xr strtoul 3 , 115.Xr wcstod 3 116.Sh STANDARDS 117The 118.Fn strtod 119function 120conforms to 121.St -isoC . 122.Sh AUTHORS 123The author of this software is 124.An David M. Gay . 125.Pp 126Copyright (c) 1991 by AT&T. 127.Pp 128Permission to use, copy, modify, and distribute this software for any 129purpose without fee is hereby granted, provided that this entire notice 130is included in all copies of any software which is or includes a copy 131or modification of this software and in all copies of the supporting 132documentation for such software. 133.Pp 134THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED 135WARRANTY. IN PARTICULAR, NEITHER THE AUTHOR NOR AT&T MAKES ANY 136REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY 137OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE. 138.Pp 139Contact your vendor for a free copy of the source code to 140.Fn strtod 141and accompanying functions. 142