Re: Compiling kernel with SuSE 8.2/gcc 3.3

From: Andreas Schwab (
Date: Wed Jun 11 2003 - 11:12:04 EST

Steve French <> writes:

|> I also noticed lots of compiler warnings with gcc 3.3, now default in
|> SuSE, and cleaned up most of them for the cifs vfs but there are a few
|> that just
|> look wrong for gcc to spit out warnings on. For example the following
|> local variable definition and the similar ones in the same file
|> (fs/cifs/inode.c):
|> __u64 uid = 0xFFFFFFFFFFFFFFFF;
|> generates a warning saying the value is too long for a long on x86 SuSE
|> 8.2 with gcc 3.3 - which makes no sense. Any value
|> above 0xFFFFFFFFF generates the same warning (intuitively
|> 36 bits should fit in an unsigned 64 bit local variable).

An expression is evaluated independent of the context, ie. the fact that
the left side of the assignment is a 64 bit variable has no significance
at all. But I agree that the warning should only occur in c89 mode, not
in the default gnu89 mode, where long long is available. And in fact the
generated code will be correct.

|> Defining the literal with the UL suffix didn't seem to help

Yes, since you need a long long literal.

|> rebelled against the solutions that work for this case ie casting the
|> local variable which is already __u64 to __u64 but that presumably would
|> work for those three, as would a (__u64)cast of -1 which seems equally
|> ugly).

You can just use -1. The implicit conversion to __u64 will DTRT.


Andreas Schwab, SuSE Labs,
SuSE Linux AG, Deutschherrnstr. 15-19, D-90429 Nürnberg
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