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Annotation of 43BSD/contrib/icon/rt/pow.c, revision 1.1.1.1

1.1       root        1: #include   <errno.h>
                      2: int errno;
                      3: double log(), exp();
                      4: /*
                      5:  * pow - calculate arg1^arg2.
                      6:  */
                      7: double
                      8: pow(arg1,arg2)
                      9: double arg1, arg2;
                     10:    {
                     11:    double temp;
                     12:    long l;
                     13: 
                     14:    if(arg1 <= 0.) {
                     15:       if(arg1 == 0.) {
                     16:          if(arg2 <= 0.)
                     17:             goto domain;
                     18:          return(0.);
                     19:       }
                     20:       l = arg2;
                     21:       if(l != arg2)
                     22:          goto domain;
                     23:       temp = exp(arg2 * log(-arg1));
                     24:       if(l & 1)
                     25:          temp = -temp;
                     26:       return(temp);
                     27:    }
                     28:    return(exp(arg2 * log(arg1)));
                     29: 
                     30: domain:
                     31:    errno = EDOM;
                     32:    return(0.);
                     33:    }

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