Reference

atof(3)

convert ASCII string to double

NAME

atof – convert ASCII string to double

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <stdlib.h>

double

atof(const char *nptr);

DESCRIPTION

The atof() function converts the initial portion of the string pointed to by nptr to double representation.

It is equivalent to:

strtod(nptr, (char **)NULL);

The decimal point character is defined in the program's locale (category LC_NUMERIC).

IMPLEMENTATION NOTES

The atof() function is not thread-safe and also not async-cancel-safe.

The atof() function has been deprecated by strtod() and should not be used in new code.

ERRORS

The function atof() need not affect the value of errno on an error.

SEE ALSO

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

STANDARDS

The atof() function conforms to ISO/IEC 9945-1:1990 (“POSIX.1”), ISO/IEC 9899:1990 (“ISO C90”), and ISO/IEC 9899:1999 (“ISO C99”).

HISTORY

The atof() function appeared in Version 1 AT&T UNIX.

History