On Saturday, 21 April 2018 at 23:47:41 UTC, Mike Franklin wrote:
On Saturday, 21 April 2018 at 19:06:52 UTC, Steven
Schveighoffer wrote:
alloca is an intrinsic, and part of the language technically
-- it has to be.
From what I can tell `alloca` is only available in the
platform's C standard library (actually for Linux it appears be
part of libgcc as `__builtin_alloca`; `alloca` is just and
alias for it).
Of course I can use 3rd party libraries like C to do this, but
it seems like something useful to have in the language for
certain use case and optimizations. Also, my immediate use
case if for bare metal microcontroller programming where I'm
intentionally avoid C and looking for a way to do this in
idiomatic D.
Mike
As you have discovered alloca is a builtin: this is true for LDC,
GDC and DMD, it's true for clang and i suspect most C/C++
compilers.
You're not using the C library version of it, the compiler does
the stack space reservation inline for you. There is no way
around this.
Use `std.experimental.allocator.building_blocks.Region` with a
slice from `alloca`.
or if you just want the memory
scope T[] arr = (cast(T*)alloca(n*T.sizeof))[0 .. n];
