http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56153
Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |manu at gcc dot gnu.org
--- Comment #3 from Manuel López-Ibáñez <manu at gcc dot gnu.org> 2013-01-30
19:11:19 UTC ---
I always found the wording of the warning confusing. This is what clang says:
test.c:12:46: warning: operand of ? changes signedness: 'int' to 'unsigned int'
[-Wsign-conversion]
fprintf (stdout, "%d", foo != 0 ? foo->num : -1);
~~~~~~~ ^~
And this is what GCC 4.8 says:
/home/manuel/test.c:12:44: warning: signed and unsigned type in conditional
expression [-Wsign-compare]
fprintf (stdout, "%d", foo != 0 ? foo->num : -1);
^
Note also the different location information.
Note the description of -Wsign-compare:
"Warn when a comparison between signed and unsigned values could produce an
incorrect result when the signed value is converted to unsigned. "
which does not match this warning. It does match the description of
-Wsign-conversion:
"Warn for implicit conversions that may change the sign of an integer value,
like assigning a signed integer expression to an unsigned integer variable."
When using -Wsign-conversion, GCC emits an additional warning:
/home/manuel/test.c:12:1: warning: negative integer implicitly converted to
unsigned type [-Wsign-conversion]
fprintf (stdout, "%d", foo != 0 ? foo->num : -1);
^
(with awful location info).
