NAME

atof, atof_l — convert ASCII string to double

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <stdlib.h>

double
atof(const char *str);

#include <xlocale.h>

double
atof_l(const char *str, locale_t loc);

DESCRIPTION

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

It is equivalent to:

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

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

While the atof() function uses the current locale, the atof_l() function may be passed a locale directly. See xlocale(3) for more information.

IMPLEMENTATION NOTES

The atof() and atof_l() functions are thread-safe and async-cancel-safe.

The strtod() and strtod_l() functions are recommended instead of atof() and atof_l() functions, especially 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), xlocale(3)

STANDARDS

The atof() function conforms to IEEE Std 1003.1-1990 (“POSIX.1”), ISO/IEC 9899:1990 (“ISO C90”), and ISO/IEC 9899:1999 (“ISO C99”).