1al_fixadd(3)               Library Functions Manual               al_fixadd(3)
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NAME

6       al_fixadd
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SYNOPSIS

9              #include <allegro5/allegro.h>
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11              al_fixed al_fixadd(al_fixed x, al_fixed y);
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DESCRIPTION

14       Although  fixed  point  numbers  can be added with the normal + integer
15       operator, that doesn't provide any  protection  against  overflow.   If
16       overflow  is  a  problem,  you should use this function instead.  It is
17       slower than using integer operators, but if an overflow occurs it  will
18       set  Allegro's  errno and clamp the result, rather than just letting it
19       wrap.
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21       Example:
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23                  al_fixed result;
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25                  /* This will put 5035 into `result'. */
26                  result = al_fixadd(al_itofix(5000), al_itofix(35));
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28                  /* Sets errno and puts -32768 into `result'. */
29                  result = al_fixadd(al_itofix(-31000), al_itofix(-3000));
30                  assert(!al_get_errno()); /* This will fail. */
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RETURN VALUE

33       Returns the clamped result of adding x to y, setting Allegro's errno to
34       ERANGE if there was an overflow.
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SEE ALSO

37       al_fixsub(3), al_fixmul(3), al_fixdiv(3).
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41Allegro reference manual                                          al_fixadd(3)