Annex D (normative) Compatibility features [depr]

D.11 C headers [depr.c.headers]

D.11.6 Header <tgmath.h> synopsis [depr.tgmath.h.syn]

#include <cmath> #include <complex>
The header <tgmath.h> behaves as if it simply includes the headers <cmath> and <complex>.
[Note 1:
The overloads provided in C by type-generic macros are already provided in <complex> and <cmath> by “sufficient” additional overloads.
— end note]
[Note 2:
Names introduced by <cmath> or <complex> in namespace std are not placed into the global namespace scope by <tgmath.h>.
— end note]