error: no named 'auto_ptr' in namespace 'std'

[mrashad32]

Hi all,

Some of the libc++ tests that use std::auto_ptr (like [this one]) currently fail to compile with LLVM 19 when using -std=c++20.
The error is:

error: no member named 'auto_ptr' in namespace 'std'
This is expected, since auto_ptr was removed in C++17.
However, in older versions like LLVM 17, these tests could still be compiled by defining: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS

Would it make sense to add this is macro in test builds, to allow testing auto_ptr-related code for those maintaining legacy projects? _LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR

Thanks!

[frederick-vs-ja]

We're doing this per test file (as the comment is recognized by lit).

llvm-project/libcxx/test/libcxx/depr/depr.auto.ptr/auto.ptr/auto_ptr.cxx1z.pass.cpp

Lines 18 to 19 in 4551e50

	// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR
	// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS

[mrashad32]

We're doing this per test file (as the comment is recognized by lit).

llvm-project/libcxx/test/libcxx/depr/depr.auto.ptr/auto.ptr/auto_ptr.cxx1z.pass.cpp

Lines 18 to 19 in 4551e50

// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR
// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS

Thanks a lot for the clarification!

I noticed that some other tests using std::auto_ptr—like this one:
auto_ptr_Y.pass.cpp—don’t currently include the -D_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR flag.

Would it make sense to open a pull request to add the necessary ADDITIONAL_COMPILE_FLAGS to those tests, so they continue to compile in C++17 and later when legacy support is needed?

[ldionne]

That test contains // REQUIRES: c++03 || c++11 || c++14, so we don't need to enable the removed auto_ptr.