Pure variants of C's memory allocation functions
realloc and deallocation function
extern(C) void* pureRealloc (
) pure nothrow @nogc;
UNIX 98 requires that errno be set to ENOMEM upon failure.
However, this is irrelevant for DMD's purposes, and best practice
protocol for using errno is to treat it as an
out parameter, and not
something with state that can be relied on across function calls.
So, we'll ignore it.
D's rules for purity, which allow for memory allocation under specific circumstances.
Walter Bright, https://www.digitalmars.com