[diff.cpp03.diagnostics]

# Annex C (informative) Compatibility [[diff]](./#diff)

## C.6 C++ and ISO C++ 2003 [[diff.cpp03]](diff.cpp03#diagnostics)

### C.6.9 [[diagnostics]](diagnostics "19 Diagnostics library"): diagnostics library [diff.cpp03.diagnostics]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/compatibility.tex#L2509)

**Affected subclause:** [[errno]](errno)  


**Change:** Thread-local error numbers[.](#1.sentence-1)

  


**Rationale:** Support for new thread facilities[.](#1.sentence-2)

  


**Effect on original feature:** Valid but implementation-specific C++ 2003 code that relies onerrno being the same across threads may change behavior in this
revision of C++[.](#1.sentence-3)