The function rndtonl in the phobos package core.math is defined, but it isn't available in the library's object file. Here's an example program that fails at link time.
```
import core.math;
import std;
void main()
{
const lval = rndtonl(5.0L);
writeln("lval = %d", lval);
}
```
Here's the dmd linking error as reported by https://run.dlang.io.
```
./onlineapp.d:6: error: undefined reference to 'rndtonl'
collect2: error: ld returned 1 exit status
Error: linker exited with status 1
```