libstdc++: compiling with iostream header: error: unknown type name 'char_traits'

[Jonathan Wakely]

On 20 June 2010 16:42, Nobin Mathew wrote:
>
> I think in stringfwd.h _GLIBCXX_BEGIN_NAMESPACE(std) is parsed for the
> first time.

That should be defined by bits/c++config.h, and works fine when
compiled by g++, which is the only supported use of the libstdc++
headers.

If clang fails to process the headers then either clang has a bug, you
do not have some required configuration needed to make it work.
Technically this can't be a bug in libstdc++, because using clang is
not supported.  However, we would consider specific changes to make
the headers work with clang if there is a real problem.

I suggest you find out how clang parses your bits/c++config.h and why
_GLIBCXX_BEGIN_NAMESPACE doesn't get defined to something useful.  You
should start by examining the preprocessed output to see what
_GLIBCXX_BEGIN_NAMESPACE(std) expands to.

It seems that your testcase is unnecessary, the following program
should produce the same problem:

#include <ios>
int main() { }