c++ - Is initializing a VLA with braces a GCC bug or extension? -

c++ - Is initializing a VLA with braces a GCC bug or extension? -

with next code in mind:

int main() { int n = 3; int arr[n] = { 1, 2, 3 }; }

gcc errors out in c99 mode error: variable-sized object may not initialized , clang gives same error in c++ mode. in c++ mode, gcc doesn't complain. lead me believe it's perchance extension that's not documented on c extensions vla page. couldn't find matching bug study either. can verify if extension or if there's existing bug report?

this new behaviour is mentioned in suspect may correlated gcc 4.9 release notes:

g++ supports c++1y variable length arrays. g++ has supported gnu/c99-style vlas long time, now additionally supports initializers , lambda capture reference. in c++1y mode g++ complain vla uses not permitted draft standard, such forming pointer vla type or applying sizeof vla variable. note appears vlas not part of c++14, part of separate document , perhaps c++17.

note default standard mode c++ still gnu++98/gnu++03 release.

c++ c gcc variable-length-array