Re: Providing diagnostic information upon successful completion

"albrecht.fritzsche" <>
7 Nov 2006 18:58:05 -0500
Nicola Musatti wrote:

I'm looking for advice on how to provide diagnostic information related
to a function call that executed successfully.


What do you people think? Do you see alternative strategies?

I realise that this is exactly what Aspect Oriented Programming is all
about, but I have a low level library rather than an application or a
framework; the decision to use such a strategic approach is best left
to the users of my library.

Hi Nicola,

For low-level libs a function pointer might be the appropriate
alternative. Ie, the low-level functions have an additional parameter
where the client /might/ pass in a function pointer to a trace or
logging function

// interface
typedef void (*log_cb)(const char*);
void foo(log_cb cb=0);

// implementation
struct Logger {
      Logger(const char* name, log_cb cb=0) : name_(name), cb_(cb) {}
      ~Logger() { if (cb_) cb_(name_); }
      const char* name_;
      log_cb cb_;

void foo(log_cb cb) { Logger logger("foo", cb); }

// usage
void trace(const char* text) { cout << text << endl; }

int main() {
      return 0;

Several issues still need to be considered

   - above Logger logs on every, ie even on exceptional, exit
   - if logging is lib-wide then it's tedious to pass the fp to every func
   - ...

but at least the user has now already an easy way to "register" its
personal logging function.


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