/********************************************************************** * Copyright (c) Digital Equipment Corporation 1984, 1985, 1986. * * All Rights Reserved. * * Reference "/usr/src/COPYRIGHT" for applicable restrictions. * **********************************************************************/ /* SCCSID: @(#)pow.c 3.0 4/22/86 */ /* computes a^b. uses log and exp */ #include <errno.h> int errno; double log(), exp(); double pow(arg1,arg2) double arg1, arg2; { double temp; long l; if(arg1 <= 0.) { if(arg1 == 0.) { if(arg2 <= 0.) goto domain; return(0.); } l = arg2; if(l != arg2) goto domain; temp = exp(arg2 * log(-arg1)); if(l & 1) temp = -temp; return(temp); } return(exp(arg2 * log(arg1))); domain: errno = EDOM; return(0.); }