View Source: strtod(3) - Waikato Linux Users Group

Edit PageHistory Diff Info LikePages

STRTOD
!!!STRTOD
NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
CONFORMING TO
SEE ALSO
----
!!NAME


strtod, strtof, strtold - convert ASCII string to floating point number
!!SYNOPSIS


__#include __


__double strtod(const char *__''nptr''__, char
**__''endptr''__);
float strtof(const char *__''nptr''__, char
**__''endptr''__);
long double strtold(const char *__''nptr''__, char
**__''endptr''__);__
!!DESCRIPTION


The __strtod__, __strtof__, and __strtold__
functions convert the initial portion of the string pointed
to by ''nptr'' to __double__, __float__, and
__long double__ representation,
respectively.


The expected form of the (initial portion of the) string is
optional leading white space as recognized by ''is-
space''(3), an optional plus (``+'') or minus sign (``-'')
and then either (i) a decimal number, or (ii) a hexadecimal
number, or (iii) an infinity, or (iv) a NAN
(not-a-number).


A ''decimal number'' consists of a nonempty sequence of
decimal digits possibly containing a radix character
(decimal point, locale dependent, usually ``.''), optionally
followed by a decimal exponent. A decimal exponent consists
of an ``E'' or ``e'', followed by an optional plus or minus
sign, followed by a non-empty sequence of decimal digits,
and indicates multiplication by a power of 10.


A ''hexadecimal number'' consists of a ``0x'' or ``0X''
followed by a nonempty sequence of hexadecimal digits
possibly containing a radix character, optionally followed
by a binary exponent. A binary exponent consists of a ``P''
or ``p'', followed by an optional plus or minus sign,
followed by a non-empty sequence of decimal digits, and
indicates multiplication by a power of 2. At least one of
radix character and binary exponent must be
present.


An ''infinity'' is either ``INF'' or ``INFINITY'',
disregarding case.


A ''NAN'' is ``NAN'' (disregarding case) optionally
followed by `(', a sequence of characters, followed by ')'.
The character string specifies in an
implementation-dependent way the type of NAN.
!!RETURN VALUE


These functions return the converted value, if
any.


If ''endptr'' is not __NULL__, a pointer to the
character after the last character used in the conversion is
stored in the location referenced by
''endptr''.


If no conversion is performed, zero is returned and the
value of ''nptr'' is stored in the location referenced by
''endptr''.


If the correct value would cause overflow, plus or minus
__HUGE_VAL__ (__HUGE_VALF__, __HUGE_VALL__) is
returned (according to the sign of the value), and
__ERANGE__ is stored in ''errno''. If the correct
value would cause underflow, zero is returned and
__ERANGE__ is stored in ''errno''.
!!ERRORS


__ERANGE__


Overflow or underflow occurred.
!!CONFORMING TO


ANSI C describes __strtod__, C99 describes the other two
functions.
!!SEE ALSO


atof(3), atoi(3), atol(3),
strtol(3), strtoul(3)
----

14 pages link to strtod(3):

This page is a man page (or other imported legacy content). We are unable to automatically determine the license status of this page.

Last edited on Tuesday, June 4, 2002 12:24:36 am by "perry"

Edit PageHistory Diff Info LikePages