On 5/4/2013 12:24 PM, Olaf Peter wrote:
Hello,
the code here doesn't compile:
#include
#include <iostream> namespace mpl = boost::mpl;
typedef mpl::string<'h','e','l','l','o',' ','w','o','r','l','d'>::type my_hello;
int main() { std::cout << mpl::c_str
::value << '\n'; std::cout << BOOST_MPL_LIMIT_STRING_SIZE << '\n'; } As usual, the example from docs works. The error is:
$ LANG=en g++ t.cpp -o t && ./t t.cpp:6:64: error: wrong number of template arguments (11, should be 8) /usr/local/include/boost/mpl/string.hpp:102:12: error: provided for 'template
struct boost::mpl::string' t.cpp:6:72: error: expected initializer before 'my_hello' t.cpp: In function 'int main()': t.cpp:10:26: error: 'my_hello' was not declared in this scope t.cpp:10:34: error: template argument 1 is invalid why does it complain about wrong number of template arguments? BOOST_MPL_LIMIT_STRING_SIZE is 32?
$ svn info ... Path: . URL: http://svn.boost.org/svn/boost/trunk Repository Root: http://svn.boost.org/svn/boost Repository UUID: b8fc166d-592f-0410-95f2-cb63ce0dd405 Revision: 83988 ... $ LANG=en g++ --version g++ (GCC) 4.6.3 20120306 (Red Hat 4.6.3-2) ...
Have you tried: typedef mpl::string<'hell','o wo','rld'>::type my_hello; ? BOOST_MPL_LIMIT_STRING_SIZE is a count of "characters" in the mpl::string, which is 4X the number of template parameters, since mpl::string uses multi-character literals to pack 4 characters into an int. HTH, -- Eric Niebler Boost.org http://www.boost.org