What's the C++ suffix for long double literals?

Walter picture Walter · Feb 4, 2014 · Viewed 45.3k times · Source

In C++ (and C), a floating point literal without suffix defaults to double, while the suffix f implies a float. But what is the suffix to get a long double?

Without knowing, I would define, say,

const long double x = 3.14159265358979323846264338328;

But my worry is that the variable x contains fewer significant bits of 3.14159265358979323846264338328 than 64, because this is a double literal. Is this worry justified?

Answer

Vlad from Moscow picture Vlad from Moscow · Feb 4, 2014

From the C++ Standard

The type of a floating literal is double unless explicitly specified by a suffix. The suffixes f and F specify float, the suffixes l and L specify long double.

It is interesting to compare with corresponding paragraph of the C Standard. In C there is used term floating constant instead of floating literal in C++:

4 An unsuffixed floating constant has type double. If suffixed by the letter f or F, it has type float. If suffixed by the letter l or L, it has type long double