mirror of
https://github.com/KolibriOS/kolibrios.git
synced 2024-12-23 23:26:49 +03:00
73 lines
2.1 KiB
C
73 lines
2.1 KiB
C
|
/*
|
||
|
|
FUNCTION
|
||
|
|
<<atof>>, <<atoff>>---string to double or float
|
||
|
|
|
||
|
|
INDEX
|
||
|
|
atof
|
||
|
|
INDEX
|
||
|
|
atoff
|
||
|
|
|
||
|
|
ANSI_SYNOPSIS
|
||
|
|
#include <stdlib.h>
|
||
|
|
double atof(const char *<[s]>);
|
||
|
|
float atoff(const char *<[s]>);
|
||
|
|
|
||
|
|
TRAD_SYNOPSIS
|
||
|
|
#include <stdlib.h>
|
||
|
|
double atof(<[s]>)
|
||
|
|
char *<[s]>;
|
||
|
|
|
||
|
|
float atoff(<[s]>)
|
||
|
|
char *<[s]>;
|
||
|
|
|
||
|
|
DESCRIPTION
|
||
|
|
<<atof>> converts the initial portion of a string to a <<double>>.
|
||
|
|
<<atoff>> converts the initial portion of a string to a <<float>>.
|
||
|
|
|
||
|
|
The functions parse the character string <[s]>,
|
||
|
|
locating a substring which can be converted to a floating-point
|
||
|
|
value. The substring must match the format:
|
||
|
|
. [+|-]<[digits]>[.][<[digits]>][(e|E)[+|-]<[digits]>]
|
||
|
|
The substring converted is the longest initial
|
||
|
|
fragment of <[s]> that has the expected format, beginning with
|
||
|
|
the first non-whitespace character. The substring
|
||
|
|
is empty if <<str>> is empty, consists entirely
|
||
|
|
of whitespace, or if the first non-whitespace character is
|
||
|
|
something other than <<+>>, <<->>, <<.>>, or a digit.
|
||
|
|
|
||
|
|
<<atof(<[s]>)>> is implemented as <<strtod(<[s]>, NULL)>>.
|
||
|
|
<<atoff(<[s]>)>> is implemented as <<strtof(<[s]>, NULL)>>.
|
||
|
|
|
||
|
|
RETURNS
|
||
|
|
<<atof>> returns the converted substring value, if any, as a
|
||
|
|
<<double>>; or <<0.0>>, if no conversion could be performed.
|
||
|
|
If the correct value is out of the range of representable values, plus
|
||
|
|
or minus <<HUGE_VAL>> is returned, and <<ERANGE>> is stored in
|
||
|
|
<<errno>>.
|
||
|
|
If the correct value would cause underflow, <<0.0>> is returned
|
||
|
|
and <<ERANGE>> is stored in <<errno>>.
|
||
|
|
|
||
|
|
<<atoff>> obeys the same rules as <<atof>>, except that it
|
||
|
|
returns a <<float>>.
|
||
|
|
|
||
|
|
PORTABILITY
|
||
|
|
<<atof>> is ANSI C. <<atof>>, <<atoi>>, and <<atol>> are subsumed by <<strod>>
|
||
|
|
and <<strol>>, but are used extensively in existing code. These functions are
|
||
|
|
less reliable, but may be faster if the argument is verified to be in a valid
|
||
|
|
range.
|
||
|
|
|
||
|
|
Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
|
||
|
|
<<lseek>>, <<read>>, <<sbrk>>, <<write>>.
|
||
|
|
*/
|
||
|
|
|
||
|
|
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <_ansi.h>
|
||
|
|
|
||
|
|
double
|
||
|
|
_DEFUN (atof, (s),
|
||
|
|
_CONST char *s)
|
||
|
|
{
|
||
|
|
return strtod (s, NULL);
|
||
|
|
}
|