Hello,
On 4/29/13 3:01 PM, Richard Fuchs wrote:
Hi,
On 04/29/13 07:11, Daniel-Constantin Mierla wrote:
Hello,
On 4/10/13 3:36 PM, Richard Fuchs wrote:
-int db_mysql_free_result(db1_con_t* _h, db1_res_t* _r); +int db_mysql_free_result(const db1_con_t* _h, db1_res_t* _r);
the change to the prototype of the above function is now throwing compilation warning:
km_db_mysql.c: In function ‘db_mysql_bind_api’: km_db_mysql.c:109: warning: assignment from incompatible pointer type
Do you need the const specifier? If yes, the DB API and probably the other database drivers need to be updated.
The const is needed because db_mysql_free_result is called from other functions which have the db1_con_t object declared as const. Removing the const from the prototype would trigger warnings elsewhere.
The idea is that the driver-specific result set should really be stored in the db1_res_t object, and not in db1_con_t as the other drivers do it now (which was causing the segfault). Therefore, ->free_result really has no reason to modify the db1_con_t object, which warrants the const modifier. Preferably the other drivers should be updated to follow the same reasoning, after which the const can be put into db_func_t, but I don't have enough experience with them to do it myself.
Alternatively, the const could probably be removed from this and a few other function prototypes, or maybe a wrapper function could be used.
your patch is incomplete/wrong in a way or another -- you introduced a warning in the piece of code you changed. It will be still wrong if the warning will be in another place, so choosing one instead of the other is not a solution.
You can probably cast to const whenever it is required so by a calling function, rather than changing the prototype and leaving it with warning like this, if you don't know how to/can't update the other drivers for various reasons.
Cheers, Daniel