cmath vs math.h (And similar c-prefixed vs .h extension headers)
c++, header, include
Solution
I've seen some information about differences between things like iostream vs iostream.h.
[iostream.h] is not a standard header.
it is not an example of the issue you're raising.
[cmath] defines symbols in the `std` namespace, and may also define symbols in the global namespace. [math.h] defines symbols in the global namespace, and may also define symbols in the `std` namespace. if you include the former and use an unqualified symbol, it may compile with one compiler but not with another. therefore it's a good idea to use [math.h]. and in general, for such header pairs, to use the [.h] version.
c++98 provided a formal guarantee of the c`xxx` header not polluting the global namespace. maybe that was why they were defined. however, that was a bit harder to implement than polluting ones, so in practice no standard library implementation that i know of followed the standard in this respect, and so it was finally changed to reflect reality in c++11.
Problem
I've seen some information about differences between things like `iostream` vs `iostream.h`. From what I gathered from those the difference between them is that the version without the `.h` extension will not populate the namespace while the version with the extension will. Is this the same for `cmath` vs `math.h`? Why is `cmath` (and many other files like it) prefixed with a `c` instead of just being `math`? Are there more differences between them?