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Diffstat (limited to 'flang/docs/C++17.md')
| -rw-r--r-- | flang/docs/C++17.md | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/flang/docs/C++17.md b/flang/docs/C++17.md index b20364b..f36110a 100644 --- a/flang/docs/C++17.md +++ b/flang/docs/C++17.md @@ -153,3 +153,8 @@ signifies a successful recognition and absence denotes a failed parse. It is used in data structures in place of nullable pointers to avoid indirection as well as the possible confusion over whether a pointer is allowed to be null. + +`std::optional<bool>` is commonly used to denote a "tri-state" +logical value that might be unknown. +Please try to avoid implicit casts of `std::optional<bool>` to `bool`, +and use `.value_or(default)` or `.has_value()` instead as appropriate. |