atof man page

atof — convert a string to a double


#include <stdlib.h>

double atof(const char *nptr);


The atof() function converts the initial portion of the string pointed to by nptr to double. The behavior is the same as

strtod(nptr, NULL);

except that atof() does not detect errors.

Return Value

The converted value.


For an explanation of the terms used in this section, see attributes(7).

atof()Thread safetyMT-Safe locale

Conforming to

POSIX.1-2001, POSIX.1-2008, C89, C99, SVr4, 4.3BSD.

See Also

atoi(3), atol(3), strfromd(3), strtod(3), strtol(3), strtoul(3)


This page is part of release 4.09 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at

Referenced By

atoi(3), mawk(1), strfromd(3), strtod(3), strtol(3), strtonum(3), strtoul(3).

2016-12-12 GNU Linux Programmer's Manual