when declaring an empty struct like struct {}; there should be a parse error when compiling with -std=c99, since there seem to be no grammar rule in the c-standard[1] which allows the empty curled braces in a struct declaration. visual studio 2003 and the edg parser report this as a parse error.
[1] http://www.open-std.org/JTC1/SC22/WG14/www/docs/n1124.pdf -- Summary: parse error expected at empty struct declaration Product: gcc Version: 3.4.4 Status: UNCONFIRMED Severity: minor Priority: P2 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: alexander dot floh at fh-hagenberg dot at http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24253