1380092 - error: cannot convert ‘std::nullptr_t’ to ‘uintptr_t {aka unsigned int}’

Status: RESOLVED FIXED

(Core :: IPC, defect)

Description

[Tom Ritter [:tjr] (OOTO until 4/30 at least)]

I get the following error when building with MinGW:

> In file included from /home/tom/Documents/moz/mingw-work/just-build-6/obj-mingw/ipc/mscom/Unified_cpp_ipc_mscom0.cpp:56:0:
> /home/tom/Documents/moz/mingw-work/just-build-6/ipc/mscom/Utils.cpp: In function ‘uintptr_t mozilla::mscom::GetContainingModuleHandle()’:
> /home/tom/Documents/moz/mingw-work/just-build-6/ipc/mscom/Utils.cpp:95:12: error: cannot convert ‘std::nullptr_t’ to ‘uintptr_t {aka unsigned int}’ in return
>   return nullptr;

https://stackoverflow.com/questions/13092266/why-cant-nullptr-convert-to-int explains why it is not valid to cast nullptr to an int and https://stackoverflow.com/questions/1845482/what-is-uintptr-t-data-type#1846648 explains that uintptr_t is an unsigned int that happens to be large enough to hold a pointer.

Based on these, I believe that the use of nullptr here is incorrect and it should instead be NULL.

Comment 1

[Tom Ritter [:tjr] (OOTO until 4/30 at least)]

Attachment: Bug 1380092 Return 0 instead of nullptr

nullptr is explicitly not allowed to be cast to an int.
But uintptr_t is an unsigned int that happens to be large
enough to hold a pointer.

Return NULL, which is allowed to be cast to an int.

Review commit: https://reviewboard.mozilla.org/r/156248/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/156248/

Comment 2

[Jed Davis [:jld] ⟨⏰|UTC-7⟩ ⟦he/him⟧]

Comment on attachment 8885400 [details]
Bug 1380092 Return 0 instead of nullptr

https://reviewboard.mozilla.org/r/156248/#review161404

I'd use 0 instead of NULL, since it's an integer type.

Comment 3

[Tom Ritter [:tjr] (OOTO until 4/30 at least)]

Comment on attachment 8885400 [details]
Bug 1380092 Return 0 instead of nullptr

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/156248/diff/1-2/

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/f4a8816b477d
Return 0 instead of nullptr r=jld

Comment 5

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/f4a8816b477d