'\" t .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) .\" .\" SPDX-License-Identifier: Linux-man-pages-copyleft .\" .\" References consulted: .\" Linux libc source code .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) .\" 386BSD man pages .\" Modified Mon Mar 29 22:39:24 1993, David Metcalfe .\" Modified Sat Jul 24 21:39:22 1993, Rik Faith (faith@cs.unc.edu) .TH atof 3 2023-10-31 "Linux man-pages 6.06" .SH NAME atof \- convert a string to a double .SH LIBRARY Standard C library .RI ( libc ", " \-lc ) .SH SYNOPSIS .nf .B #include .P .BI "double atof(const char *" nptr ); .fi .SH DESCRIPTION The .BR atof () function converts the initial portion of the string pointed to by \fInptr\fP to .IR double . The behavior is the same as .P .in +4n .EX strtod(nptr, NULL); .EE .in .P except that .BR atof () does not detect errors. .SH RETURN VALUE The converted value. .SH ATTRIBUTES For an explanation of the terms used in this section, see .BR attributes (7). .TS allbox; lbx lb lb l l l. Interface Attribute Value T{ .na .nh .BR atof () T} Thread safety MT-Safe locale .TE .SH STANDARDS C11, POSIX.1-2008. .SH HISTORY POSIX.1-2001, C89, C99, SVr4, 4.3BSD. .SH SEE ALSO .BR atoi (3), .BR atol (3), .BR strfromd (3), .BR strtod (3), .BR strtol (3), .BR strtoul (3)