On Thursday, 27 September 2018 at 23:53:50 UTC, Steven
Schveighoffer wrote:
On 9/27/18 8:16 AM, Atila Neves wrote:
On Tuesday, 25 September 2018 at 14:13:50 UTC, Jacob Carlborg
wrote:
On Tuesday, 25 September 2018 at 12:05:21 UTC, Jonathan M
Davis wrote:
If you use -betterC, then it's trivial, because your D
program is restricted to extern(C) functions and features
which don't require druntime. It can also be done without
-betterC (and thus with druntime), but it gets to be _way_
more of a pain, because it requires that you manually
initialize druntime - either by forcing whatever is using
your "C" library to call a specific function to initialize
druntime before using any of its normal functions or by
having every function in the library check whether druntime
has been initialized yet and initialize it if it hasn't been
before it does whatever it's supposed to do.
Shouldn't it be possible to use a C initialization function,
i.e. pragma(crt_constructor) to initialize druntime? Then it
only needs to be initialized once and it's not required to
check if it's initialized all the time.
--
/Jacob Carlborg
Even easier, compile this C file and add the resulting object
file to your (now mostly) D static library:
-----------------------
extern int rt_init(void);
extern int rt_term(void);
__attribute__((__constructor__)) void dinit(void) {
rt_init();
}
__attribute__((__destructor__)) void dterm(void) {
rt_term();
}
-----------------------
The C runtime will initialise the D runtime for you.
I will point out that this is EXACTLY what
pragma(crt_constructor) does.
Really? Huh. You live, you learn. I didn't even know that pragma
existed - it's not listed here at all:
https://dlang.org/spec/pragma.html
And my comments still aren't answered -- I'm not sure whether
this works correctly or not, as we don't test initializing
druntime before C main runs.
It's worked for me in practice.
Since C initialization functions have no order to them, it's
possible that some initialization functions in the D runtime
are using uninitialized pieces of the C runtime
No, that can't happen. The C runtime is initialised no matter
what you do (unless you write `_start` yourself), _then_ the
global constructors are run. The code I wrote isn't standard C -
it's just that gcc/clang/cl are all also C++ compilers so they
chose to extend the already existing functionality to C.
