1fixmul(3)                       Allegro manual                       fixmul(3)
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NAME

6       fixmul  - Multiplies two fixed point values together. Allegro game pro‐
7       gramming library.
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SYNOPSIS

10       #include <allegro.h>
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13       fixed fixmul(fixed x, fixed y);
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DESCRIPTION

16       A fixed point value can be multiplied or divided by an integer with the
17       normal  `*'  and  `/'  operators.  To  multiply two fixed point values,
18       though, you must use this function.
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20       If an overflow occurs, `errno' will be set  and  the  maximum  possible
21       value  will be returned, but `errno' is not cleared if the operation is
22       successful. This means that if you are going to test for  overflow  you
23       should set `errno=0' before calling fixmul(). Example:
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25          fixed result;
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27          /* This will put 30000 into `result'. */
28          result = fixmul(itofix(10), itofix(3000));
29          /* But this overflows, and sets `errno'. */
30          result = fixmul(itofix(100), itofix(3000));
31          ASSERT(!errno);
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RETURN VALUE

34       Returns  the  clamped result of multiplying `x' by `y', setting `errno'
35       to ERANGE if there was an overflow.
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SEE ALSO

39       fixadd(3), fixsub(3), fixdiv(3),  ex3buf(3),  excustom(3),  exfixed(3),
40       exspline(3), exstars(3), exupdate(3)
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44Allegro                          version 4.2.2                       fixmul(3)
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