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
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('''