15 Preprocessing directives [cpp]

15.4 Resource inclusion [cpp.embed]

15.4.2 Embed parameters [cpp.embed.param]

15.4.2.3 suffix parameter [cpp.embed.param.suffix]

1
#
An embed-parameter of the form
suffix ( pp-balanced-token-seq )
shall appear at most once in the embed-parameter-seq.
2
#
If the resource is empty, this embed-parameter is ignored.
Otherwise, the pp-balanced-token-seq is placed immediately after the comma-delimited list of the integral constant expressions.
[Example 1: constexpr unsigned char whl[] = { #embed "ches.glsl" \ prefix(0xEF, 0xBB, 0xBF, ) /* a sequence of bytes */ \ suffix(,) 0 }; // always null-terminated, contains the sequence if not empty constexpr bool is_empty = sizeof(whl) == 1 && whl[0] == '\0'; constexpr bool is_not_empty = sizeof(whl) >= 4 && whl[sizeof(whl) - 1] == '\0' && whl[0] == '\xEF' && whl[1] == '\xBB' && whl[2] == '\xBF'; static_assert(is_empty || is_not_empty); — end example]