Headers                                          complex.h(3HEAD)



NAME
     complex.h, complex - complex arithmetic

SYNOPSIS
     #include 


DESCRIPTION
     The  header defines the following macros:

     complex         Expands to Complex.


     ComplexI      Expands to a  constant  expression  of  type
                     const  float Complex, with the value of the
                     imaginary unit (that is,  a  number  i  such
                     that i^2=-1).


     imaginary       Expands to Imaginary.


     ImaginaryI    Expands to a  constant  expression  of  type
                     const float Imaginary with the value of the
                     imaginary unit.


     I               Expands   to    either    ImaginaryI    or
                     ComplexI. If ImaginaryI is  not defined,
                     I expands to ComplexI.



     An application can undefine and then, if appropriate,  rede-
     fine the complex, imaginary, and I macros.

USAGE
     Values are interpreted as radians, not degrees.

ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:













SunOS 5.11          Last change: 17 Dec 2003                    1






Headers                                          complex.h(3HEAD)



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface Stability          Standard                    
    


SEE ALSO
     cabs(3M),  cacos(3M),   cacosh(3M),   carg(3M),   casin(3M),
     casinh(3M),   catan(3M),  catanh(3M),  ccos(3M),  ccosh(3M),
     cexp(3M),   cimag(3M),   clog(3M),    conj(3M),    cpow(3M),
     cproj(3M),   creal(3M),   csin(3M),   csinh(3M),  csqrt(3M),
     ctan(3M), ctanh(3M), attributes(5), standards(5)

NOTES
     The choice of I instead of i for the imaginary unit concedes
     to  the  widespread  use  of the identifier i for other pur-
     poses. The application can use a different  identifier,  say
     j,  for the imaginary unit by following the inclusion of the
      header with:

       #undef I
       #define j ImaginaryI



     An  I  suffix  to  designate  imaginary  constants  is   not
     required,  as  multiplication  by  I provides a sufficiently
     convenient and more generally useful notation for  imaginary
     terms. The corresponding real type for the imaginary unit is
     float, so that use of I for algorithmic or  notational  con-
     venience does not result in widening types.


     On systems with imaginary types,  the  application  has  the
     ability  to control whether use of the macro I introduces an
     imaginary type, by explicitly defining I to be  ImaginaryI
     or ComplexI.


     Disallowing imaginary types is useful for some  applications
     intended  to run on implementations without support for such
     types.


     The macro ImaginaryI provides a test for whether imaginary
     types  are supported. The cis() function (cos(x) ] I*sin(x))
     was considered but rejected because  its  implementation  is
     easy  and  straightforward, even though some implementations
     could compute sine and cosine more efficiently in tandem.





SunOS 5.11          Last change: 17 Dec 2003                    2