Use nullptr (C++11) instead of zero (0) as the null pointer constant #10645

practicalswift · 2017-06-21T19:12:46Z

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

jtimon · 2017-06-22T01:26:32Z

utACK a0fbff2c8c0621d2ef4759078b3c690f1c33748b

gmaxwell

Concept ACK

practicalswift · 2017-06-22T19:06:42Z

Rebased!

…the pointer literal instead of the macro NULL 90d4d89 scripted-diff: Use the C++11 keyword nullptr to denote the pointer literal instead of the macro NULL (practicalswift) Pull request description: 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 #10483 (scripted, this PR) * `0` → `nullptr` is handled in PR #10645 (manual) Tree-SHA512: 3c395d66f2ad724a8e6fed74b93634de8bfc0c0eafac94e64e5194c939499fefd6e68f047de3083ad0b4eff37df9a8a3a76349aa17d55eabbd8e0412f140a297

practicalswift · 2017-08-14T15:40:34Z

@laanwj Thanks for merging the NULL → nullptr PR (#10483). This PR handles the case 0 → nullptr and has now been rebased on top of master.

laanwj · 2017-08-14T17:45:01Z

utACK f71710d

jnewbery

Tested ACK f71710dad454f5afe431479d0aea578b36d68206. Looks good @practicalswift . Thanks for doing this!

One open question for @laanwj

jnewbery · 2017-08-15T21:03:14Z

src/tinyformat.h

@@ -898,7 +898,7 @@ class FormatListN : public FormatList
 // Special 0-arg version - MSVC says zero-sized C array in struct is nonstandard
 template<> class FormatListN<0> : public FormatList
 {
-    public: FormatListN() : FormatList(0, 0) {}
+    public: FormatListN() : FormatList(nullptr, 0) {}


There may be an argument to not making style changes to tinyformat.h, which occasionally pulls in changes from upstream. Don't know what @laanwj's view is on this?

Agree, we should generally minimize changes to tinyformat.h, and if it is just style it just adds burden on us with no clear gain.

If you get upstream to accept this it's okay with me. But I think they want to keep compatiblity with older C++.

practicalswift · 2017-08-16T08:25:35Z

@jnewbery @laanwj Good point! The change to src/tinyformat.h is no longer included in this PR.

…nter 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 #10483 (scripted) * `0` → `nullptr` is handled in PR #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

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 #10483 * `0 → nullptr` was handled in the recently merged PR #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

…(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