Hello, I'm trying to add an option to sql_mode. For this, I'm adding in sql_class.h : #define MODE_CONCAT_NULL_YIELDS_NULL (1ULL << 32) But now, my serveur doesn't start and show "Sysvar 'sql_mode' failed 'def_val <= my_set_bits(typelib.count)'" The problem seems to be in sys_vars.ic (Sys_var_set) : { option.var_type|= GET_SET; global_var(ulonglong)= def_val; SYSVAR_ASSERT(typelib.count > 0); SYSVAR_ASSERT(typelib.count <= 64); SYSVAR_ASSERT(def_val <= my_set_bits(typelib.count)); SYSVAR_ASSERT(size == sizeof(ulonglong)); } Function my_set_bits works on 32bit and typelib.count may be up to 64. In my case typelib.count is 33 and my_set_bits(33) returns 1, and the assert is false. What is my mistake ? Best regards, Jérôme.