When I read that error I wondered why anyone would define a function for threads with the same name as a well established C function. On a closer look it revealed to be just another name for the same extern(C) memcpy to avoid the import of core.stdc.string in core.thread:
private { import core.sync.mutex; import core.atomic; // // from core.memory // extern (C) void gc_enable(); extern (C) void gc_disable(); extern (C) void* gc_malloc(size_t sz, uint ba = 0); // // from core.stdc.string // extern (C) void* memcpy(void*, const void*, size_t); // // exposed by compiler runtime // extern (C) void rt_moduleTlsCtor(); extern (C) void rt_moduleTlsDtor(); alias void delegate() gc_atom; extern (C) void function(scope gc_atom) gc_atomic; } Well, it is mildly annoying. `private` doesn't really help in the way the author expected it to work here. -- Marco