As an extension, GNU C supports additional floating
__float128 to support 80-bit
XFmode) and 128-bit (
TFmode) floating types.
Support for additional types includes the arithmetic operators:
add, subtract, multiply, divide; unary arithmetic operators;
relational operators; equality operators; and conversions to and from
integer and other floating types. Use a suffix ‘w’ or ‘W’
in a literal constant of type
__float80 and ‘q’ or ‘Q’
_float128. You can declare complex types using the
corresponding internal complex type,
typedef _Complex float __attribute__((mode(TC))) _Complex128; typedef _Complex float __attribute__((mode(XC))) _Complex80;
Not all targets support additional floating-point types.
__float128 types are supported on x86 and IA-64 targets.
__float128 type is supported on hppa HP-UX targets.