float128: Add strfromf128, strtof128, and wcstof128 to the manual

	* manual/math.texi (Mathematics): Add description for _FloatN and
	_FloatNx types and mentions that they are not support in glibc for
	any architecture, so far.
	* manual/arith.texi (wcstof, wcstold): Replace the mention to
	stdlib.h with wchar.h.
	(Parsing of Floats): Add descriptions for strtofN and wcstofN.
	(Printing of Floats): Add description for strfromfN.

1 files changed, 11 insertions, 0 deletions

diff --git a/manual/math.texi b/manual/math.texi
index 69a0acec9b..53c2bc1a1f 100644
--- a/manual/math.texi
+++ b/manual/math.texi
@@ -53,6 +53,17 @@ usually wise to pick the narrowest type that can accommodate your data.
 Not all machines have a distinct @code{long double} type; it may be the
 same as @code{double}.
 
+On some machines, @theglibc{} also provides @code{_Float@var{N}} and
+@code{_Float@var{N}x} types.  These types are defined in @w{ISO/IEC TS
+18661-3}, which extends @w{ISO C} and defines floating-point types that
+are not machine-dependent.  When such a type, such as @code{_Float128},
+is supported by @theglibc{}, extra variants for most of the mathematical
+functions provided for @code{double}, @code{float}, and @code{long
+double} are also provided for the supported type.
+
+Currently, support for @code{_Float@var{N}} or @code{_Float@var{N}x}
+types is not provided for any machine.
+
 @menu
 * Mathematical Constants::      Precise numeric values for often-used
                                  constants.