Using pinvoke in c# to call sprintf and friends on 64-bit
- by bde
I am having an interesting problem with using pinvoke in C# to call _snwprintf. It works for integer types, but not for floating point numbers.
This is on 64-bit Windows, it works fine on 32-bit.
My code is below, please keep in mind that this is a contrived example to show the behavior I am seeing.
class Program
{
[DllImport("msvcrt.dll", CharSet = CharSet.Unicode, CallingConvention = CallingConvention.Cdecl)]
private static extern int _snwprintf([MarshalAs(UnmanagedType.LPWStr)] StringBuilder str, uint length, String format, int p);
[DllImport("msvcrt.dll", CharSet = CharSet.Unicode, CallingConvention = CallingConvention.Cdecl)]
private static extern int _snwprintf([MarshalAs(UnmanagedType.LPWStr)] StringBuilder str, uint length, String format, double p);
static void Main(string[] args)
{
Double d = 1.0f;
Int32 i = 1;
Object o = (object)d;
StringBuilder str = new StringBuilder();
_snwprintf(str, 32, "%10.1f", (Double)o);
Console.WriteLine(str.ToString());
o = (object)i;
_snwprintf(str, 32, "%10d", (Int32)o);
Console.WriteLine(str.ToString());
Console.ReadKey();
}
}
The output of this program is
0.0
1
It should print 1.0 on the first line and not 0.0, and so far I am stumped.
