Re: [PATCH, PR C++/61038] - g++ -E is unusable with UDL strings

["Joseph S. Myers" <joseph at codesourcery dot com>]

On Mon, 12 May 2014, Ed Smith-Rowland wrote:

> This patch is really a libcpp patch.  But UDLs are like that ;-)
> 
> Add string user-defined literals and char user-defined literals to the list of
> things to look out for while escaping strings in macro args.
> 
> I'm not sure how to test this really.  we want to write out *.ii files and
> verify that internal quotes are escaped.

You should be able to check the results of stringizing twice, e.g.:

extern "C" int strcmp (const char *, const char *);
extern "C" void abort (void);
extern "C" void exit (int);

void operator "" _s(const char *, unsigned long)
{
}

#define QUOTE(s) #s
#define QQUOTE(s) QUOTE(s)

const char *s = QQUOTE(QUOTE("hello"_s));
const char *t = QUOTE("\"hello\"_s");

int main()
{
  if (strcmp(s, t) == 0)
    exit(0);
  else
    abort();
}

(at least, this fails for me with unmodified GCC, and I think it should 
pass).

-- 
Joseph S. Myers
joseph@codesourcery.com