consider template<typename T, typename... Args> T max( T a, T b, Args... args
);
template<typename T> T max( T a)
{
return a;
}
template<typename T, typename... Args> T max( T a, T b, Args... args )
{
return a > max<T>(b, args...) ? a : max<T>(b, args...);
}
#include <iostream>
int main()
{
std::cout << max(3u, 2u, -1) << std::endl;
}
Guess, what it prints: 4294967295
That means, the -1 is converted from signed int to unsigned int in the call to
max(2u, -1) [ with T = unsigned int, Args = ], which may not occur in a
template lookup! The call should be rejected as invalid by the compiler,
because it must not find a definition for max(unsigned int, int).
This happens only in the recursion of the variadic template, calling max(3u,
-1) is rejected as desired.
gcc version 4.3.0-20080111
--
Summary: Invalid conversion in lookup of variadic template
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: rbuergel at web dot de
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34877
