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Information in this article applies to:

  • C166 All Versions
  • C251 All Versions
  • C51 All Versions


I've noticed that in many places interrupt routines defined in C are declared with the static keyword. For example:

static void ISR (void) interrupt 0

Why is that?


It's just good practice to declare the ISR static. The static keyword makes the interrupt function invisible to functions outside the file where it is defined. This makes sense because the interrupt function can't actually be called by another function.

Last Reviewed: Friday, December 17, 2004

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