For compatibility with prior C++International Standards, the C++standard library provides headers <ccomplex> ([depr.ccomplex.syn]), <cstdalign> ([depr.cstdalign.syn]), <cstdbool> ([depr.cstdbool.syn]), and <ctgmath> ([depr.ctgmath.syn]). The use of these headers is deprecated.
#include <complex>
#define __alignas_is_defined 1
#define __bool_true_false_are_defined 1
#include <complex> #include <cmath>
The header <ctgmath> simply includes the headers <complex> ([complex.syn]) and <cmath> ([cmath.syn]).