clang++ unable to recognize 'nullptr' without flag

Question

I am running:

Apple clang version 14.0.0 (clang-1400.0.29.202)
Target: x86_64-apple-darwin22.2.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin

when I run: clang++ *.cpp -o test, I get:

    identifier = nullptr;
                  ^
1 error generated.

however, when I run: clang++ -std=c++11 *.cpp -o test, I get no errors.

Does anyone else have this issue with the latest version of clang?

Whoever set the duplicate flag, this is not a duplicate. I had made the reasonable assumption that the latest version of clang wouldn't be running C++98 by default. Also, the linked post is from 10 years ago, when C++11 got released...

Answer 1

Apple clang++ 14.0.0 defaults to C++98.

For example with this source file:

long version = __cplusplus;
void *p = nullptr;

You can see this behavior:

$ clang++ -E nullptr.cpp | grep -v '^#'
long version = 199711L;
void *p = nullptr;

$ clang++ -c nullptr.cpp           
nullptr.cpp:2:11: error: use of undeclared identifier 'nullptr'
void *p = nullptr;
          ^
1 error generated.

$ clang++ -c -std=c++11 nullptr.cpp

The solution is to explicitly request a language standard of C++11 or newer via -std=c++XY, as shown above.