Q exponent-letter (The GNU Fortran Compiler)

#### 5.1.9 ‘`Q`’ exponent-letter ¶

GNU Fortran accepts real literal constants with an exponent-letter of ‘`Q`’, for example, `1.23Q45`. The constant is interpreted as a `REAL(16)` entity on targets that support this type. If the target does not support `REAL(16)` but has a `REAL(10)` type, then the real-literal-constant is interpreted as a `REAL(10)` entity. In the absence of `REAL(16)` and `REAL(10)`, an error occurs.