410708 - Compiler warning in nsUTF8Utils.h

Status: RESOLVED FIXED

(Core :: XPCOM, defect)

Description

[Ryan VanderMeulen [:RyanVM]]

Since the landing of bug 396052, I'm seeing the following warning when compiling nsBrowserApp.cpp:
d:\mozbuild\mozilla\objdir-fx\dist\include\string\nsUTF8Utils.h(702) : warning C4309: '=' : truncation of constant value

Comment 1

[[e-mail]]

http://bonsai.mozilla.org/cvsblame.cgi?file=/mozilla/xpcom/string/public/nsUTF8Utils.h&rev=1.18#618

maybe buffer_type should be unsigned char?

Comment 2

[Serge Gautherie (:sgautherie)]

What I'm currently seeing on multiple files, on Win2000:
{{
../../dist/include/string\nsUTF8Utils.h(579) : warning C4309: '=' : truncation of constant value
../../dist/include/string\nsUTF8Utils.h(580) : warning C4309: '=' : truncation of constant value
../../dist/include/string\nsUTF8Utils.h(581) : warning C4309: '=' : truncation of constant value
../../dist/include/string\nsUTF8Utils.h(606) : warning C4309: '=' : truncation of constant value
../../dist/include/string\nsUTF8Utils.h(607) : warning C4309: '=' : truncation of constant value
../../dist/include/string\nsUTF8Utils.h(608) : warning C4309: '=' : truncation of constant value
../../dist/include/string\nsUTF8Utils.h(626) : warning C4309: '=' : truncation of constant value
../../dist/include/string\nsUTF8Utils.h(627) : warning C4309: '=' : truncation of constant value
../../dist/include/string\nsUTF8Utils.h(628) : warning C4309: '=' : truncation of constant value
}}

Comment 3

[Serge Gautherie (:sgautherie)]

Attachment: (Av1) Add explicit cast, to 'buffer_type'

[Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.9.1a2pre) Gecko/2008072915 Minefield/3.1a2pre] (home made) (W2Ksp4)

Comment 4

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Comment on attachment 331624 [details] [diff] [review]
(Av1) Add explicit cast, to 'buffer_type'

>-                    *out++ = 0xEF;
>-                    *out++ = 0xBF;
>-                    *out++ = 0xBD;
>+                    *out++ = (buffer_type) 0xEF;
>+                    *out++ = (buffer_type) 0xBF;
>+                    *out++ = (buffer_type) 0xBD;

If it fixes it, I'd prefer:

*out++ = '\xEF';
etc.

If not (which would surprise me), I'd prefer construction-style casts:

*out++ = buffer_type(0xEF);
etc.

Comment 5

[Serge Gautherie (:sgautherie)]

Attachment: (Av2) Use char notation [Checkin: Comment 7]

[Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.9.1a2pre) Gecko/20080809033244 Minefield/3.1a2pre] (home, optim default) (W2Ksp4)

Av1, with comment 4 suggestion(s).

Comment 6

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Comment on attachment 333051 [details] [diff] [review]
(Av2) Use char notation
[Checkin: Comment 7]

r+sr=dbaron

Comment 7

[Rob Arnold [:robarnold]]

Pushed to mozilla-central:
http://hg.mozilla.org/mozilla-central/index.cgi/rev/0c93feec361e