这是调用分配内存的调用. hbitmap是返回的指针,需要解除分配.
[DllImport("twain_32.dll",EntryPoint = "#1")]
public static extern TwainResult DsImageTransfer(
[In,Out] Identity origin,[In] Identity dest,DataGroup dg,DataArgumentType dat,Message msg,ref IntPtr hbitmap);
解决方法
更新
如果我冒昧猜测,twain_32.dll中调用的函数#1是TWAIN提供程序中的DS_ENTRY函数. Twain specifications调出内存资源管理协议：
Memory Management in TWAIN 2.0 and
Higher
TWAIN requires Applications and
Sources to manage each other’s memory.
The chief problem is guaranteeing
agreement on the API’s to use. TWAIN
2.0 introduces four new functions that are obtained from the Source Manager
through DAT_ENTRYPOINT.
TW_HANDLE PASCAL DSM_MemAllocate (TW_UINT32)
PASCAL DSM_MemFree (TW_HANDLE)
TW_MEMREF PASCAL DSM_MemLock(TW_HANDLE)
void PASCAL DSM_MemUnlock(TW_HANDLE)These functions correspond to the
WIN32 Global Memory functions
mentioned in prevIoUs versions of the
TWAIN Specification:GlobalAlloc,
GlobalFree,GlobalLock,GlobalUnlock
On MacOS/X these functions call
NewPtrClearandDisposePtr. The lock
and unlock functions are no-ops,but
they still must be called. TWAIN 2.0
compliant Applications and Sources
must use these calls on all platforms
(Windows,MacOS/X and Linux). The
Source Manager takes the
responsibility to make sure that all
components are using the same memory
management API’s.
所以为了释放资源,你应该调用DSM_MemFree,据说Win32平台将通过GlobalFree或Marshal.FreeHGlobal实现.
由于这主要是我的猜测,您最好使用您使用的特定TWAIN实现的规范进行验证.
