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Comment by brownleej | Hacker News Reader

I see void being passed as a parameter list to main in a lot of examples. All of the things I've read suggest that the only difference between having a void parameter list and an empty parameter list is in function declarations, and that the two are equivalent in function definitions. Why is it used so frequently in the main function definition, if it serves no purpose?

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You've probably been reading C++ material. Only in C++

  int f();

and

  int f(void);

are identical.

In C, however,

  int f();

Declares a function taking any number of arguments. In C++, that would be denoted as

  int f(...);

Which is unfortunately a syntax error in traditional C as the ellipsis is only allowed following some explicit parameters. (It's not that big a deal; you'd have to

  #ifdef __cplusplus
  extern "C"
  #endif

in the header of the C library for C++ compatibility anyway (to prevent function name mangling and thus link errors), so you can #ifdef the () and (...) too.)

FWIW, C++ does support the legacy

  int f(void);

syntax, but its use is discouraged except for headers which are also to be used for C code.

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