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How would you guys connect C Library/Function (incl. Callback) to your c++ code?
SeppyQT last edited by
this question is rather theoretic question but I have already encountered this problem.
There are some C Libraries like CURL, OpenSSL, WolfSSL, aso, which have Functions which expect a Function pointer as Argument.
Since you can't pass Member Function Pointers and you can't pass Lambdas with captures in it, how do you work around?
this function accepts a callback Function pointer
int(*)(SSL*,unsigned char*,unsigned int);
In most curl functions you can work around by passing this pointer as void* userdata to a static or standalone function which forwards back to class. But in this example it is not possible. How do you implement C Functions in your C++ code?
mpergand last edited by mpergand
The simplest method is to use a static function with the correct signature in a cpp class .
here what i'm doing for two callbacks functions from the Mac Coreaudio midi API.
static void MIDINotifyProc(const MIDINotification *msg, void *refCon); static void MIDIReadProc(const MIDIPacketList *pkList, void *refCon, void *con);
You can implement a pure C function as well, but you may need to declare the function as extern "C" for correct linkage (not tested, hope i'm not wrong :-) )