scripted-diff: Use the C++11 keyword nullptr to denote the pointer literal instead of the macro NULL #10483

practicalswift · 2017-05-31T08:03:38Z

Since C++11 the macro NULL may be:

an integer literal with value zero, or
a prvalue of type std::nullptr_t

By using the C++11 keyword nullptr we are guaranteed a prvalue of type std::nullptr_t.

For a more thorough discussion, see "A name for the null pointer: nullptr" (Sutter &
Stroustrup), http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2431.pdf

With this patch applied there are no NULL macro usages left in the repo:

$ git grep NULL -- "*.cpp" "*.h" | egrep -v '(/univalue/|/secp256k1/|/leveldb/|_NULL|NULLDUMMY|torcontrol.*NULL|NULL cert)' | wc -l
0

The road towards nullptr (C++11) is split into two PRs:

NULL → nullptr is handled in PR scripted-diff: Use the C++11 keyword nullptr to denote the pointer literal instead of the macro NULL #10483 (scripted, this PR)
0 → nullptr is handled in PR Use nullptr (C++11) instead of zero (0) as the null pointer constant #10645 (manual)

jonasschnelli · 2017-05-31T08:37:09Z

Concept ACK

dcousens

utACK

laanwj · 2017-06-01T08:27:53Z

Concept ACK. I think we can all agree that this needs to be done at some point, though we'll have to discuss when to do this with the least impact. This change probably means every single PR needs to be rebased.

practicalswift · 2017-06-04T16:53:41Z

Rebased!

sipa · 2017-06-04T18:20:20Z

Can you rewrite this as a series of scripted diffs (possibly mixed with a few manual commits to fix things up)? See #10189 #10193 #10502 #10321 for examples.

As for timing, possibly immediately after the feature freeze?

practicalswift · 2017-06-08T14:29:52Z

@sipa Great idea! Now re-implemented as a scripted-diff. Looks good? :-)

sipa · 2017-06-08T20:12:56Z

@practicalswift You can use sed -i 's/\<NULL\>/nullptr/g' for the main operation. \< and \> denote begin and end of word.

practicalswift · 2017-06-09T15:26:50Z

@sipa Good point! Now using s/\<NULL\>/nullptr/g. Looks good? :-)

practicalswift · 2017-06-11T13:53:20Z

Merge conflicts resolved!

practicalswift · 2017-06-13T09:23:26Z

What is the correct protocol to follow w.r.t. rebasing a large scripted-diff PR such as this one?

Should I rebase periodically myself to keep it mergeable, or should I wait until I'm asked to rebase prior to the suggested time for merge (@sipa suggested: "possibly immediately after the feature freeze").

maflcko · 2017-06-13T10:20:29Z

@practicalswift It is sufficient to rebase only once. Please refer to #9961 (comment) for the preliminary date of feature freeze.

practicalswift · 2017-06-13T10:36:30Z

@MarcoFalke Great! Thanks for clarifying!

theuni · 2017-06-13T20:54:00Z

Concept ACK. It'd be helpful to compare before/after binaries.

…(void*)0 bea8e9e Document the preference of nullptr over NULL or (void*)0 (practicalswift) Pull request description: Document the preference of `nullptr` over `NULL` or `(void*)0`. After this commit: ``` $ git grep "[^A-Za-z_]NULL[^A-Za-z_]" | grep -vE '(leveldb|univalue|secp256k1|torcontrol|NULL certificates|ctaes|release-notes|patches|configure.ac|developer-notes)' $ ``` Some context: * `NULL → nullptr` was handled in the recently merged PR bitcoin#10483 * `0 → nullptr` was handled in the recently merged PR bitcoin#10645 Tree-SHA512: f863096aa4eb21705910f89713ca9cc0d83c6df2147e3d3530c3e1589b96f6c68de8755dcf37d8ce99ebda3cfb69805e00eab13bf65424aaf16170e9dda3958a

…ull pointer constant 36d326e Use nullptr instead of zero (0) as the null pointer constant (practicalswift) Pull request description: Use `nullptr` instead of zero (0) as the null pointer constant. The road towards `nullptr` (C++11) is split into two PRs: * `NULL` → `nullptr` is handled in PR bitcoin#10483 (scripted) * `0` → `nullptr` is handled in PR bitcoin#10645 (manual, this PR) By using the C++11 keyword `nullptr` we are guaranteed a prvalue of type `std::nullptr_t`. For a more thorough discussion, see "A name for the null pointer: nullptr" (Sutter & Stroustrup), http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2431.pdf Tree-SHA512: 5412404b40a94ea2d9fc8f81573559c4ffe559749301d486b09d41a7a736345ad602d08ac590930bb00a49692b6075520cf3d543e4da6ccd5b29fa9bcc3f15ea