On Tue, 14 Aug 2012 21:27:25 +0200, Andrew <andrew.sp...@gmail.com> wrote:
I'm trying to interface with C code, where I have a function definition that takes two const char[]'s: PetscErrorCode PetscInitialize(int*, char***, const char[], const char[]); However, the typical way that you pass "Null" values instead of the last two arguments is "PETSC_NULL" The problem is that PETSC_NULL is a macro defined to be 0. I can't do the normal "int PETSC_NULL = 0" thing, because it doesn't follow the type signature of PetscInitialize. How to I pass 0 in place of the last two arguments? cast(const char[])(0) doesn't work, and just an empty string ("\0") doesn't work either. -Andrew
I'm a tad confused. Why can't you just pass null? In D, the literal 0 is not implicitly convertible to void*, char***, or any other pointer or reference type, so instead you should use the literal null, which has no nameable type, but is implicitly converted to any pointer or reference type you may wish. If you really want to, you can have enum PETSC_NULL = null; so that you can write PetscInitialize( &i, PETSC_NULL, PETSC_NULL ), but I'd recommend just using the null we have. -- Simen