> From: Richard Stallman <[EMAIL PROTECTED]> > CC: [EMAIL PROTECTED], emacs-pretest-bug@gnu.org, [EMAIL PROTECTED] > Date: Tue, 16 Jan 2007 00:16:54 -0500 > > I think we should demand some way to turn off the warning in specific > places. Does GCC have a feature to turn off warnings in a specific > piece of code? I don't remember. It would be a good feature to have.
I don't think GCC has something like this. But even if it had, such features in other compilers either reference a warning by its code (something like W4589), or by the command-line switch that turns that warning off globally. The former is both ugly and unreadable, to say nothing of maintainability. The latter requires that a command-line option exist to control the warning, which in this particular case we don't have. > However, a specific feature just for this kind of warning would also > be useful. I have an idea for what it could look like: an extra cast. > > if ((int)(short)foo > (int)SHRT_MAX || (int)(short)foo < (int)SHRT_MIN) This won't work in the context such as our FIXNUM_OVERFLOW_P macro, since it is specifically needs to DTRT when `foo' is not a short, but int or long. But even if this worked, I think it obfuscates the code too much. I don't know what important situations triggered the introduction of this warning at such a basic level of diagnostics, but the result is that GCC now flags perfectly valid and legitimate code as questionable. I think this is unacceptable when GCC runs without any "-Wxxx" option. So I think we should ask GCC maintainers to produce this warning only under -Wall. I think this is the best alternative, on balance. Tests like the above are about the only valid way in C to test the width of data types, so GCC should not flag it as suspicious unless asked to. _______________________________________________ emacs-pretest-bug mailing list emacs-pretest-bug@gnu.org http://lists.gnu.org/mailman/listinfo/emacs-pretest-bug
