Question

I have a function in C++ that returns pointer values​​:

fPosFirst( int &aId, char *aNname, char *aDirectory );

My syntax in c# is:

fPosFirst(ref int aId,  String aNname,  String aDirectory);

the function returns the id but not the string parameters that anyone knows?

Answer 1

Assuming that the native function does not “return pointers” but writes characters to the memory locations specified by aNname and aDirectory, you should be able to pass a StringBuilder with a proper capacity to the native function:

void fPosFirst(ref int aId, StringBuilder aNname, StringBuilder aDirectory);

Usage:

var aId = 0;
var aNname = new StringBuilder(260);
var aDirectory = new StringBuilder(260);

fPosFirst(ref aId, aNname, aDirectory);