Condider this
/* bar.c */
void bar(char a)
{
char b = a;
}
void frob(void)
{
bar('a');
}
Due to the automatic promotion of char to int in function calls [same would
apply to short or C99 _Bool], then this causes a warning with -Wconversion,
thus:
gcc -Wconversion -c bar.c
bar.c: In function 'frob':
bar.c:10: warning: passing argument 1 of 'bar' with different width due to
prototype
This greatly limits the usefulness of -Wconversion.
As a user I either have to
a) put up with many thousands of useless warnings
b) not use -Wconversion, or use it with heavy filtering
c) never pass char/short/bool arguments in functions
A similar thing happens with float/double:
bar.c:10: warning: passing argument 1 of 'bar' as 'float' rather than 'double'
due to prototype
This only happens with gcc, not g++.
--
Summary: Excessive warnings when using -Wconversion and
char/bool/short function arguments
Product: gcc
Version: 4.0.2
Status: UNCONFIRMED
Severity: minor
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: paulf at free dot fr
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38121
