About macros of protothreads

Hello,

In the header file "pt.h", most of the macros like PT_WAIT_UNTIL,
PT_SPAWN, etc are implemented with a do-while loop. For an example:

#define PT_WAIT_UNTIL(pt, condition)	 \
  do {						         \
    LC_SET((pt)->lc);				         \
    if(!(condition)) {				         \
      return PT_WAITING;			         \
    }						                 \
  } while(0)

As it appears, the do-while loop does do nothing. I may be asking a
simple question. Is there any special reason to use such a do-while
loop here?

Thank you.

..:: කසුන් චන්ද්‍රනාත් ::..
..:: Kasun Chandranath ::..

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