Way to override/overload D’s runtime assertions to use custom handlers?

[Mike Franklin]

On Wednesday, 25 July 2018 at 15:24:50 UTC, Alexander Nicholi 
wrote:
> Is there a way to change this to use our own handlers with the 
> D runtime?

You can provide your own implementations of the runtime hooks at 
https://github.com/dlang/druntime/blob/cb5efa9854775c5a72acd6870083b16e5ebba369/src/core/exception.d#L628

extern(C) void _d_assertp(immutable(char)* file, uint line)
{
     import core.stdc.stdio;
     printf("Houston, we have a problem at %s:%u\n", file, line);
}

void main()
{
     assert(false);
}

Try it out at https://run.dlang.io/is/QZEO9W

> How does this change without the runtime, e.g. via `-betterC` 
> code?

Unfortunately, this doesn't work with -betterC because -betterC 
seems to forward runtime assertions to the C implementation.  See 
https://run.dlang.io/is/QZEO9W

For that you have to provide a new implementation of `__assert`:

extern(C) void __assert(const char *msg, const char *file, int 
line)
{
     import core.stdc.stdio;
     printf("Houston, we have a problem at %s:%u\n", file, line);
}

extern(C) void main()
{
     assert(false);
}

https://run.dlang.io/is/D5JxCT

Mike