_Complex_I

The _Complex_I macro expands to a value of type const float _Complex with the value of the imaginary unit.

[edit] Notes

This macro may be used when I is not available, such as when it has been undefined by the application.

Unlike _Imaginary_I and CMPLX, use of this macro to construct a complex number may lose the sign of zero on the imaginary part.

[edit] Example

#include <stdio.h>
#include <complex.h>
 
#undef I
#define J _Complex_I // can be used to redefine I
 
int main(void)
{
    // can be used to construct a complex number
    double complex z = 1.0 + 2.0 * _Complex_I;
    printf("1.0 + 2.0 * _Complex_I = %.1f%+.1fi\n",