osx man page for creal

CREAL(3)						   BSD Library Functions Manual 						  CREAL(3)

NAME
     creal -- complex real-part function
     cimag -- complex imaginary-part function

SYNOPSIS
     #include <complex.h>

     double
     creal(double complex z);

     long double
     creall(long double complex z);

     float
     crealf(float complex z);

     double
     cimag(double complex z);

     long double
     cimagl(long double complex z);

     float
     cimagf(float complex z);

DESCRIPTION
     creal(z) extracts the real part of the complex floating-point number z.  cimag(z) extracts the imaginary part of the complex floating-point
     number z.

     If z = x+iy, then creal(z) = x and cimag(z) = y.

EXAMPLES
     The function foo defined in the example below returns its complex argument with the imaginary part scaled by a factor of 2.

	   #include <complex.h>

	   double complex foo(double complex z) {
	     return creal(z) + 2.0*cimag(z)*I;
	   }

SEE ALSO
     complex(3)

STANDARDS
     The creal() and cimag() functions conform to ISO/IEC 9899:2011.

4th Berkeley Distribution					 December 11, 2006					 4th Berkeley Distribution