Thanks!
Jonathan Wakely-4 wrote:
>
> On 26 August 2011 15:54, Ike Starnes wrote:
>>
>> The following code builds fine in Microsoft C, but fails with gcc / g++:
>>
>>
>> #include <iostream>
>>
>> using namespace std;
>>
>> typedef struct _THREADDATA
>> {
>> int nConvTiles; // the number of swap buffers in a tiled bitmap
>> used for caching the disk tiles (default 1)
>> }
>> THREADDATA, *pTHREADDATA;
>>
>> #define DECLARETHREADDATA() pTHREADDATA pThreadData = NULL;
>> #define GETTHREADDATA() pThreadData
>> #define THREADVALUE(v) GETTHREADDATA()->##v
>>
>> static int GetTilesInfo()
>> {
>> DECLARETHREADDATA();
>> int nConvTiles;
>> nConvTiles = THREADVALUE(nConvTiles);
>> return nConvTiles;
>> }
>>
>> int main()
>> {
>> cout << "Hello world!" << endl;
>> cout << GetTilesInfo();
>> return 0;
>> }
>>
>>
>> With gcc, the error is:
>> d:\temp\GNU\HelloWorld\main.cpp:19:1: error: pasting "->" and
>> "nConvTiles"
>> does not give a valid preprocessing token
>>
>> Does anyone know the correct fix?
>
> Just remove the ## from your macro.
>
> ## is for pasting two tokens together into one, but in your macro
> there's only one token. Just get rid of it and it will work:
>
> #define THREADVALUE(v) GETTHREADDATA()->v
>
>
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