[英]Porting callback function from 32 bit to 64 bit
I am building using Visual Studio 2008 Professional. 我正在使用Visual Studio 2008专业版进行构建。 When I compile using Win32 build it compiles just fine.
当我使用Win32构建进行编译时,它可以正常编译。
But when I switch to x64 then I get this compilation error: 但是当我切换到x64时,会出现此编译错误:
error C2664: 'lineInitializeExA' : cannot convert parameter 3 from 'void (__cdecl *)(DWORD,DWORD,DWORD,DWORD,DWORD,DWORD)' to 'LINECALLBACK'
None of the functions with this name in scope match the target type
Some of the defines/typedefs:: 一些define / typedefs:
typedef unsigned long DWORD;
#define CALLBACK __stdcall
And LINECALLBACK in tapi.h is defined like this: tapi.h中的LINECALLBACK定义如下:
typedef void (CALLBACK * LINECALLBACK)(
DWORD hDevice,
DWORD dwMessage,
DWORD_PTR dwInstance,
DWORD_PTR dwParam1,
DWORD_PTR dwParam2,
DWORD_PTR dwParam3
);
On Windows unsigned long is 32 bits wide on 32 and 64 bit platform. 在Windows上,在32和64位平台上,unsigned long为32位宽。 So surely that isn't a problem.
因此,这肯定不是问题。
Any ideas why? 有什么想法吗? and how to fix?
以及如何解决?
Here is the code. 这是代码。
#include <tapi.h> // Windows tapi API
#include <stdio.h>
/*
I know it says tapi32.lib but I believe that is just old naming -
don't think 32 bit specific. and in any case don't get to linking phase
*/
#pragma comment(lib,"tapi32.lib")
void CALLBACK my_callback(DWORD dwDevice,
DWORD nMsg,
DWORD dwCallbackInstance,
DWORD dwParam1,
DWORD dwParam2,
DWORD dwParam3) {
printf("my_callback called\n");
}
int main() {
LONG result = -1;
DWORD dwAPIInit = 0x00020002;
HLINEAPP happ; // application handle
DWORD numlines; // Number of line devices in system.
result = lineInitializeEx (&happ, GetModuleHandle(0),
my_callback, "TAPITEST", &numlines, &dwAPIInit, 0);
return 0;
}
**** EDIT. ****编辑。 Not sure why, but I was seeing DWORD_PTR as:
不知道为什么,但是我看到的DWORD_PTR为:
typedef unsigned long DWORD_PTR;
But on checking is using: 但是在检查使用:
typedef ULONG_PTR DWORD_PTR, *PDWORD_PTR;
So my callback definition is wrong! 所以我的回调定义是错误的!
In terms of the arguments' declarations this 就论据的声明而言
void (CALLBACK * LINECALLBACK)(
DWORD hDevice,
DWORD dwMessage,
DWORD_PTR dwInstance,
DWORD_PTR dwParam1,
DWORD_PTR dwParam2,
DWORD_PTR dwParam3
);
isn't the same as this: 与此不同:
void CALLBACK my_callback(
DWORD dwDevice,
DWORD nMsg,
DWORD dwCallbackInstance,
DWORD dwParam1,
DWORD dwParam2,
DWORD dwParam3
):
Arguments 3 to 6 are pointers in the 1st decarations and integers in the 2nd. 参数3到6是第一个变量的指针,第二个是整数。
As omn 32bit Windows DWORD
s have the same size as pointers this might compile. 由于32位Windows
DWORD
的大小与指针的大小相同,因此可能会进行编译。
On 64bits-Windows however pointers have a different size from DWORD
s. 但是,在64位Windows上,指针的大小与
DWORD
的大小不同。
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