Check if unmanaged DLL is 32-bit or 64-bit?
Refer to the specifications. Here's a basic implementation:
public static MachineType GetDllMachineType (string dllPath)
{
// See http://www.microsoft.com/whdc/system/platform/firmware/PECOFF.mspx
// Offset to PE header is always at 0x3C.
// The PE header starts with "PE\0\0" = 0x50 0x45 0x00 0x00,
// followed by a 2-byte machine type field (see the document above for the enum).
//
using (var fs = new FileStream (dllPath, FileMode.Open, FileAccess.Read))
using (var br = new BinaryReader (fs))
{
fs.Seek (0x3c, SeekOrigin.Begin);
Int32 peOffset = br.ReadInt32();
fs.Seek (peOffset, SeekOrigin.Begin);
UInt32 peHead = br.ReadUInt32();
if (peHead != 0x00004550) // "PE\0\0", little-endian
throw new Exception ("Can't find PE header");
return (MachineType)br.ReadUInt16();
}
}
The MachineType
enum is defined as:
public enum MachineType : ushort
{
IMAGE_FILE_MACHINE_UNKNOWN = 0x0,
IMAGE_FILE_MACHINE_AM33 = 0x1d3,
IMAGE_FILE_MACHINE_AMD64 = 0x8664,
IMAGE_FILE_MACHINE_ARM = 0x1c0,
IMAGE_FILE_MACHINE_EBC = 0xebc,
IMAGE_FILE_MACHINE_I386 = 0x14c,
IMAGE_FILE_MACHINE_IA64 = 0x200,
IMAGE_FILE_MACHINE_M32R = 0x9041,
IMAGE_FILE_MACHINE_MIPS16 = 0x266,
IMAGE_FILE_MACHINE_MIPSFPU = 0x366,
IMAGE_FILE_MACHINE_MIPSFPU16 = 0x466,
IMAGE_FILE_MACHINE_POWERPC = 0x1f0,
IMAGE_FILE_MACHINE_POWERPCFP = 0x1f1,
IMAGE_FILE_MACHINE_R4000 = 0x166,
IMAGE_FILE_MACHINE_SH3 = 0x1a2,
IMAGE_FILE_MACHINE_SH3DSP = 0x1a3,
IMAGE_FILE_MACHINE_SH4 = 0x1a6,
IMAGE_FILE_MACHINE_SH5 = 0x1a8,
IMAGE_FILE_MACHINE_THUMB = 0x1c2,
IMAGE_FILE_MACHINE_WCEMIPSV2 = 0x169,
IMAGE_FILE_MACHINE_ARM64 = 0xaa64
}
I only needed three of these, but I included them all for completeness. Final 64-bit check:
// Returns true if the dll is 64-bit, false if 32-bit, and null if unknown
public static bool? UnmanagedDllIs64Bit(string dllPath)
{
switch (GetDllMachineType(dllPath))
{
case MachineType.IMAGE_FILE_MACHINE_AMD64:
case MachineType.IMAGE_FILE_MACHINE_IA64:
return true;
case MachineType.IMAGE_FILE_MACHINE_I386:
return false;
default:
return null;
}
}
Using a Visual Studio command prompt, dumpbin /headers dllname.dll works too. On my machine the beginning of the output stated:
FILE HEADER VALUES
8664 machine (x64)
5 number of sections
47591774 time date stamp Fri Dec 07 03:50:44 2007