From: 046-301-5902@kylheku.com   
      
   On 2026-01-03, Andrey Tarasevich  wrote:   
   > On Fri 1/2/2026 7:33 PM, Ben Bacarisse wrote:   
   >>   
   >> A pattern I've used more than once when setting up a table of function   
   >> pointers that act like op-codes.  Maybe you have an add function, a sub   
   >> function, a mul functions and a div function.  These are all defined in   
   >> a file arithmetic.c, but the table (maybe in another file) needs to see   
   >> declarations of the names:   
   >>   
   >> typedef double operation(double, double);   
   >> /* ... */   
   >>   
   >> extern operation add, sub, mul, div;   
   >>   
   >> static struct {   
   >>      char *name;   
   >>      operation *function;   
   >> } ops[] = {   
   >>      { "add",      add },   
   >>      { "subtract", sub },   
   >>      { "multiply", mul },   
   >>      { "divide",   div }   
   >> };   
   >>   
   >   
   > ... with a remark that `extern` is completely redundant here.   
   >   
   >    operation add, sub, mul, div;   
      
   Butlonly because operation is a function type, so the concept of   
   a tentative definition doesn't apply.   
      
   The lack of extern could trip someone up who refactors the   
   code such that the operations are object types:   
      
     named_operation add, sub, mul, div; // oops, multiple definition   
      
     static named_operation ops[] = { add, sub, mul, div };   
      
      
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