Integer constants that don't fit into a long cause a pedwarn in GCC as of the 20070907 snapshot (this has been the behavior for a while). However this is incorrect for C++0x which does (at least in the WG draft) allows for something to be placed in a long long or unsigned long long if it doesn't fit into anything smaller (section 2.13.1.2 + table 5). However GCC pedwarns even with -std=c++0x or -std=gnu++0x
(On x86-64 or other 64-bit machines this behavior can be observed while compiling with -m32). $ g++-4.3-20070907 -v Using built-in specs. Target: x86_64-unknown-linux-gnu Configured with: ../gcc-4.3-20070907/configure --program-suffix=-4.3-20070907 --enable-language=c,c++ --prefix=/home/jack/opt --with-mpfr=/home/jack/opt Thread model: posix gcc version 4.3.0 20070907 (experimental) (GCC) -- Summary: "error: integer constant is too large for ‘long’ type" incorrect for C++0x Product: gcc Version: 4.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: lloyd at randombit dot net GCC build triplet: x86_64-unknown-linux-gnu GCC host triplet: x86_64-unknown-linux-gnu GCC target triplet: x86_64-unknown-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33736