I understand what it does: specifies a string literal as a const wchar_t * (wide character string) instead of const char * (plain old characters), but how is it actually defined?
Is it a macro of some sort? Is it an operator for GCC compilers? What is it?
The literal prefixes are a part of the core language, much like the suffixes:
'a' // type: char
L'a' // type: wchar_t
"a" // type: char[2]
L"a" // type: wchar_t[2]
U"a" // type: char32_t[2]
1 // type: int
1U // type: unsigned int
0.5 // type: double
0.5f // type: float
0.5L // type: long double
Note that wchar_t has nothing to do with Unicode. Here is an extended rant of mine on the topic.
It's called an encoding prefix:
string-literal:
|encoding-prefixopt"s-char-sequenceopt"
|encoding-prefixoptRraw-string
encoding-prefix:
|u8
|u
|U
|L
and marks a wide string literal:
11) A string literal that begins with
L, such asL"asdf", is a wide string literal. A wide string literal has type “array ofnconst wchar_t”, where n is the size of the string as defined below; it has static storage duration and is initialized with the given characters.
The meaning of L here is wide character: wchar_t. String with L is coded in 16bit rather than 8bit, take an example:
"A" = 41
L"A" = 00 41
