Pass varargs to printf [duplicate]

Answer 1

The method you are looking for is vfprintf or possible vprintf (unclear which by your question)

• http://www.cplusplus.com/reference/cstdio/vfprintf/
• http://www.cplusplus.com/reference/cstdio/vprintf/

This is essentially the implementation of printf that allows a va_list to be explicitly passed in as a parameter. So in your method you can create the va_list for your method parameters and forward it onto vfprintf

void log(FILE* f, const char* format, ...) { 
  va_list args;
  va_start (args, format);
  vfprintf (f, format, args);
  va_end (args);
}