| Message ID | 1421768747-17240-2-git-send-email-peter.maydell@linaro.org |
|---|---|
| State | New |
| Headers | show |
diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py index d2f815b..1eb272d 100644 --- a/scripts/qapi-types.py +++ b/scripts/qapi-types.py @@ -99,6 +99,14 @@ struct %(name)s ret += generate_struct_fields(members) + # Make sure that all structs have at least one field; this avoids + # potential issues with attempting to malloc space for zero-length structs + # in C, and also incompatibility with C++ (where an empty struct is size 1). + if not base and not members: + ret += mcgen(''' + char qapi_dummy_field_for_empty_struct; +''') + if len(fieldname): fieldname = " " + fieldname ret += mcgen('''
Make sure that all generated C structs have at least one field; this avoids potential issues with attempting to malloc space for zero-length structs in C (g_malloc(sizeof struct) would return NULL). It also avoids an incompatibility with C++ (where an empty struct is size 1); that isn't important to us now but might be in future. Generated empty structures look like this: struct Abort { char qapi_dummy_field_for_empty_struct; }; This silences clang warnings like: ./qapi-types.h:3752:1: warning: empty struct has size 0 in C, size 1 in C++ [-Wextern-c-compat] struct Abort ^ Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 1419359069-16611-1-git-send-email-peter.maydell@linaro.org --- scripts/qapi-types.py | 8 ++++++++ 1 file changed, 8 insertions(+)