In general, when you use string parameters, use one of the buffer types if
you want the
DLL function to be able to change the contents of the
argument in TestStand. Use the C String or
Unicode String type if the
DLL
function does not modify the argument.
If you specify one of the string buffer types, the
DLL-adapter copies the contents
of the string argument and a trailing zero element into a temporary buffer
before calling the
DLL function. You specify the minimum size of the
temporary buffer in the Number of Elements control. If the string value is
longer than the buffer size you specify, the adapter resizes the temporary
buffer so that it is large enough to hold contents of the string argument and
the trailing zero element. After the
DLL function returns, TestStand copies
the value that the function writes into the temporary buffer back to the
string argument.
If you specify the C String or
Unicode String type, the adapter passes the
address of the actual string directly to the function without copying it to a
buffer. The code module must not change the contents of the string.