@comment better formatting.
@comment
@menu
+* Typedef and constants:: Defined data types and constants
* Math Library Routines:: The Libquadmath math runtime application
programming interface.
* I/O Library Routines:: The Libquadmath I/O runtime application
@c ---------------------------------------------------------------------
+@c Defined macros
+@c ---------------------------------------------------------------------
+
+@node Typedef and constants
+@chapter Typedef and constants
+
+The following data type has been defined via @code{typedef}.
+
+@table @asis
+@item @code{__complex128}: @code{__float128}-based complex number
+@end table
+
+The following macros are defined, which give the numeric limits of the
+@code{__float128} data type.
+
+@table @asis
+@item @code{FLT128_MAX}: largest finite number
+@item @code{FLT128_MIN}: smallest positive number with full precision
+@item @code{FLT128_EPSILON}: difference between 1 and the next larger
+ representable number
+@item @code{FLT128_DENORM_MIN}: smallest positive denormalized number
+@item @code{FLT128_MANT_DIG}: number of digits in the mantissa (bit precision)
+@item @code{FLT128_MIN_EXP}: maximal negative exponent
+@item @code{FLT128_MAX_EXP}: maximal positive exponent
+@item @code{FLT128_DIG}: number of decimal digits in the mantissa
+@item @code{FLT128_MIN_10_EXP}: maximal negative decimal exponent
+@item @code{FLT128_MAX_10_EXP}: maximal positive decimal exponent
+@end table
+
+The following mathematical constants of type @code{__float128} are defined.
+
+@table @asis
+@item @code{M_Eq}: the constant e (Euler's number)
+@item @code{M_LOG2Eq}: binary logarithm of 2
+@item @code{M_LOG10Eq}: common, decimal logarithm of 2
+@item @code{M_LN2q}: natural logarithm of 2
+@item @code{M_LN10q}: natural logarithm of 10
+@item @code{M_PIq}: pi
+@item @code{M_PI_2q}: two pi
+@item @code{M_PI_4q}: four pi
+@item @code{M_1_PIq}: one over pi
+@item @code{M_2_PIq}: one over two pi
+@item @code{M_2_SQRTPIq}: two over square root of pi
+@item @code{M_SQRT2q}: square root of 2
+@item @code{M_SQRT1_2q}: one over square root of 2
+@end table
+
+
+@c ---------------------------------------------------------------------
@c Math routines
@c ---------------------------------------------------------------------
@menu
* @code{strtoflt128}: strtoflt128, Convert from string
-* @code{quadmath_flt128tostr}: quadmath_flt128tostr, Convert to string
+* @code{quadmath_snprintf}: quadmath_snprintf, Convert to string
@end menu
@item Syntax
@code{__float128 strtoflt128 (const char *s, char **sp)}
-@c The return values are defined in gdtoa/gdtoa.h STRTOG_*
-@c However, the values are currently not exported - thus we
-@c do not define them here, either.
-
@item @emph{Arguments}:
@multitable @columnfractions .15 .70
@item @var{s} @tab input string
@end table
-@node quadmath_flt128tostr
-@section @code{quadmath_flt128tostr} --- Convert to string
+@node quadmath_snprintf
+@section @code{quadmath_snprintf} --- Convert to string
-The function @code{quadmath_flt128tostr} converts a @code{__float128} floating-point
-number into a string.
+The function @code{quadmath_snprintf} converts a @code{__float128} floating-point
+number into a string. It is a specialized alternative to @code{snprintf}, where
+the format string is restricted to a single conversion specifier with @code{Q}
+modifier and conversion specifier @code{e}, @code{E}, @code{f}, @code{F}, @code{g},
+@code{G}, @code{a} or @code{A}, with no extra characters before or after the
+conversion specifier. The @code{%m$} or @code{*m$} style must not be used in
+the format.
@table @asis
@item Syntax
-@code{void quadmath_flt128tostr (char *s, size_t size, size_t n, __float128 x)}
+@code{int quadmath_snprintf (char *s, size_t size, const char *format, ...)}
@item @emph{Arguments}:
@multitable @columnfractions .15 .70
@item @var{s} @tab output string
@item @var{size} @tab byte size of the string, including tailing NUL
-@item @var{n} @tab number of digits after the decimal point
-@item @var{x} @tab the number to be converted
+@item @var{format} @tab conversion specifier string
@end multitable
@item Example
@smallexample
#include <quadmath.h>
+#include <stdlib.h>
+#include <stdio.h>
int main ()
@{
__float128 r;
- char str[200];
+ int prec = 20;
+ int width = 46;
+ char buf[128];
r = 2.0q;
- r = sqrtq(r);
- quadmath_flt128tostr (str, sizeof (str), 20, r);
- printf("%s\n", str);
- /* Prints: +1.41421356237309504880e+00 */
+ r = sqrtq (r);
+ int n = quadmath_snprintf (buf, sizeof buf, "%+-#*.20Qe", width, r);
+ if ((size_t) n < sizeof buf)
+ printf ("%s\n", buf);
+ /* Prints: +1.41421356237309504880e+00 */
+ quadmath_snprintf (buf, sizeof buf, "%Qa", r);
+ if ((size_t) n < sizeof buf)
+ printf ("%s\n", buf);
+ /* Prints: 0x1.6a09e667f3bcc908b2fb1366ea96p+0 */
+ n = quadmath_snprintf (NULL, 0, "%+-#46.*Qe", prec, r);
+ if (n > -1)
+ @{
+ char *str = malloc (n + 1);
+ if (str)
+ @{
+ quadmath_snprintf (str, n + 1, "%+-#46.*Qe", prec, r);
+ printf ("%s\n", str);
+ /* Prints: +1.41421356237309504880e+00 */
+ @}
+ free (str);
+ @}
return 0;
@}
@end smallexample
+
@end table
+On some targets when supported by the C library hooks are installed
+for @code{printf} family of functions, so that @code{printf ("%Qe", 1.2Q);}
+etc.@: works too.
+
@c ---------------------------------------------------------------------
@c GNU Free Documentation License
OSDN Git Service
