Re: Using FFI to write a std::string to a buffer passed in from D

[Troy via Digitalmars-d-learn]

On Sunday, 21 July 2024 at 15:31:47 UTC, Johan wrote:
On Sunday, 21 July 2024 at 13:35:46 UTC, Troy wrote:

void create(void* b) {
        std::string s = "engineer again";
        *(std::string*)(b) = s;// Segfault here
}

You have to construct an empty string object first in location 
`b` (emplacement new). Then you can assign to it as you do.
The `=` calls `operator=` which assumes that both operands (`b` 
and `s`) are both fully constructed and valid `std::string` 
objects. Without emplacement new, `b` is not a valid 
`std::string` object (random byte buffer returned by `malloc`).

Hope that works,
  Johan

Using placement new like you suggested seems to have solved my 
issue perfectly.  I would never have never thought of that on my 
own.  Thanks for the suggestion!