CODEWITHSUNDEEP
c++compilation
wp2
wp2

Reputation: 1421

Why it compiles whether or not "extern" is used?

In a.cpp:

int t()
{
  //definition goes here
  ...
}

b.cpp:

#include "a.h"

int main()
{
  t();
}

finally a.h:

extern int t();
//int t();

Both forms of a.h works,why?

Upvotes: 1

Views: 98

Answers (1)

Lie Ryan
Lie Ryan

Reputation: 64845

Because function are extern by default, so the extern keyword is redundant. Some people like to explicitly add the extern when they want to hint other developers that the definition of the function are not to be found in the .cpp file with same name than this .h file, then they add a comment to point where the function is declared. But to the compiler's perspective, it does not affect anything.

Upvotes: 9

Related Questions