Annex D (normative) Compatibility features [depr]

D.4 C++standard library headers [depr.cpp.headers]

D.4.4 Header <ctgmath> synopsis [depr.ctgmath.syn]

#include <complex>
#include <cmath>
The header <ctgmath> simply includes the headers <complex> ([complex.syn]) and <cmath> ([cmath.syn]).
[Note
:
The overloads provided in C by type-generic macros are already provided in <complex> and <cmath> by “sufficient” additional overloads.
end note
]