Для наглядности, вот код WinAPIServer::getTempPath()
X++:
#define.maxPath(260)
public server static str getTempPath()
{
FileIOPermission fileIOPerm;
InteropPermission interopPerm;
str tempPath;
// check file I/O permission
fileIOPerm = new FileIOPermission('','r');
fileIOPerm.demand();
// get dll interop permission
interopPerm = new InteropPermission(InteropKind::ClrInterop);
interopPerm.assert();
tempPath = System.IO.Path::GetTempPath();
CodeAccessPermission::revertAssert();
return tempPath;
}