1 回答
Assuming the Jack API is written for the C language, there is a formal problem already with the working callback that you have. Namely that it then needs to be extern "C", and that as a static member function it cannot be. So formally it needs to be a free-standing function.
The documentation that you link to for the jack_set_error_function gives this signature, presumably expressed in C:
void jack_set_error_function( void(*)(const char *) func);
For C++ the callback must be assumed to be extern "C", so,
extern "C" void MyErrorFunction( char const* errorMessage )
{
// Whatever, e.g. post a message to the GUI event queue, or terminate.
}
If you want this function to in turn call a method on an object, then unless the library provides some special mechanism to help you, you will just have to use one of the following techniques:
a namespace scope variable accessed by the callback, or
a dynamically generated callback.
C++ does not as of yet support the second approach, at all, so the first one is strongly indicated – if you want a callback on a method of an object.
EDIT: Sorry, I forgot to mention,
the function declarations in the API documentation are syntactically invalid.
E.g. the documentation’s signature
void jack_set_info_function( void(*)(const char *) func );
simply won’t compile with a standard-conforming compiler. Not as C, and not as C++. It’s syntactically invalid in both languages.
Instead it should be
void jack_set_info_function( void(*func)(const char *) );
Since the documentation apparently is generated by DOxygen, it stands to reason that it's been generated from source code that compiles. If so then this is a bug in DOxygen, and a problem with the quality assurance of the library provider. However it might be a problem that lies solely with the library provider, or, I might be mistaken in the assumption that this is a C library?