There some confusing/wrong error messages with the -std=c++0x option. All three example statements below work fine without -std=c++0x and with gcc versions <= 4.3. Seems to be a gcc bug and no C++0x demand (at least the first 2 example statements).
typedef enum { AA=1, BB=2 } my_enum; typedef struct { my_enum a:4 ; unsigned b:28; } stru; void foo (char c, my_enum x, int i) { char arr[2] = {c+'0', 0}; stru s = {x,0}; stru t = {i,0}; } $ g++ -std=c++0x -c tst.c tst.c: In function 'void foo(char, my_enum, int)': tst.c:7: error: narrowing conversion of '(((int)c) + 48)' to 'char' inside { } tst.c:8: error: narrowing conversion of 'x' to 'unsigned char:4' inside { } tst.c:9: error: narrowing conversion of 'i' to 'unsigned char:4' inside { } gcc trunk rev. 141404 -- Summary: narrowing conversion with -std=c++0x Product: gcc Version: 4.4.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: holger dot hopp at sap dot com 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=37932