SPLAY_HEAD.SPLAY_HEAD

Undocumented in source but is binding to C. You might be able to learn more by searching the web for its name.
template SPLAY_HEAD(string name, string type)
extern (C) nothrow @nogc
enum SPLAY_HEAD = "struct " ~ name ~ " { " ~ type ~ "* sph_root; /* root of the tree */ }";

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