On Tue, Sep 29, 2009 at 06:38:44AM -0400, D. Richard Hipp wrote: > > On Sep 27, 2009, at 5:28 PM, Dr. David Kirkby wrote: > > > "sqlite3.c", line 18731: warning: integer overflow detected: op "<<" > > "sqlite3.c", line 18748: warning: integer overflow detected: op "<<" > > Both cases are complaining about a constant: (0x1f<<28) Both are > harmless.
They are constants, but 0x1f<<28 is being assigned to an unsigned, 32-bit integer variable, so the constant expression does overflow. The compiler is right to warn about that, even you've taken the overflow into account. I take no position on whether these warnings should be fixed. If you don't fix them though, a comment in the source (and an FAQ) would be nice, as it will head off future questions about this. If you do fix it, the fix could be to change the 1f to f, or to put an explicit cast to the type of the variable. Both are arguably dangerous fixes: what if you later change the type of those variables to be u64? I don't think that's likely in this case (varint encoding isn't going to change, is it?), but it's something to consider. If you're willing to use GNU C extensions then you could use typeof() (which Sun Studio 12 does support) in the cast expression, in which case there'd be no danger. > > "sqlite3.c", line 32546: warning: statement not reached > > Complains about this code: > > /*NOTREACHED*/ > assert( 0 ); > > Harmless. Indeed. I'm not sure why the compiler warned about this one (the NOTREACHED comment is for lint, but the compiler ought honor it). I'll ask here how to make that warning go away. > > "sqlite3.c", line 69160: warning: integer overflow detected: op "<<" > > Complains about this constant: (((sqlite3_int64)1)<<63) Harmless That too is a legitimate warning, even if you've taken the overflow into account (the compiler can't know that you did). If you move the cast to the left the warning should go away: ((sqlite3_int64)(1L<<63)), or you could use a constant for the most negative value that sqlite3_int64 can hold ((- 2^63) - 1). Nico -- _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
