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| author | Wladimir J. van der Laan <laanwj@protonmail.com> | 2020-06-29 15:17:38 +0200 |
|---|---|---|
| committer | Wladimir J. van der Laan <laanwj@protonmail.com> | 2020-06-29 15:18:26 +0200 |
| commit | fb87f6d168c45acd36d3c2b55b0647f3959c7a76 (patch) | |
| tree | d285107cd52fc49a9bc4efa012256a8dcb9b37b6 /doc | |
| parent | 19612ca2eb2e335c8ccc9c0f33421df22f1cc3b6 (diff) | |
| parent | fab57e2b9bc4577fcfcd9fbddbc35d96046c5d88 (diff) | |
Merge #19367: doc: Span pitfalls
fab57e2b9bc4577fcfcd9fbddbc35d96046c5d88 doc: Mention Span in developer-notes.md (Pieter Wuille)
3502a60418858a8281ddf2f9cd59daa8f01d2fa8 doc: Document Span pitfalls (Pieter Wuille)
Pull request description:
This is an attempt to document pitfalls with the use of `Span`, following up on comments like https://github.com/bitcoin/bitcoin/pull/18468#issuecomment-622846597 and https://github.com/bitcoin/bitcoin/pull/18468#discussion_r442998211
ACKs for top commit:
laanwj:
ACK fab57e2b9bc4577fcfcd9fbddbc35d96046c5d88
Tree-SHA512: 8f6f277d6d88921852334853c2b7ced97e83d3222ce40c9fe12dfef508945f26269b90ae091439ebffddf03f939797cb28126b2387f77959069ef8909c25ab53
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/developer-notes.md | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/doc/developer-notes.md b/doc/developer-notes.md index b33b3ad18a..bd3daa3202 100644 --- a/doc/developer-notes.md +++ b/doc/developer-notes.md @@ -620,6 +620,19 @@ class A - *Rationale*: Easier to understand what is happening, thus easier to spot mistakes, even for those that are not language lawyers. +- Use `Span` as function argument when it can operate on any range-like container. + + - *Rationale*: Compared to `Foo(const vector<int>&)` this avoids the need for a (potentially expensive) + conversion to vector if the caller happens to have the input stored in another type of container. + However, be aware of the pitfalls documented in [span.h](../src/span.h). + +```cpp +void Foo(Span<const int> data); + +std::vector<int> vec{1,2,3}; +Foo(vec); +``` + - Prefer `enum class` (scoped enumerations) over `enum` (traditional enumerations) where possible. - *Rationale*: Scoped enumerations avoid two potential pitfalls/problems with traditional C++ enumerations: implicit conversions to `int`, and name clashes due to enumerators being exported to the surrounding scope. |