[sqlite] behavior of API functions on NULL sqlite3* pointer

[avpak]

Hello.

I am trying to wrap C++ class over sqlite API.
The idea is to keep sqlite3* into smart pointer.
Unfortunately sqlite3_open function does not guarantee strong error safety.
One needs call sqlite3_close even if sqlite3_open has failed.

While exploring sqlite documentation and sources I have got the following
discrepancy:

  In documentation:
        int sqlite3_close(sqlite3*);

        Call this function with a pointer to a structure that was previously
        returned from sqlite3_open() or sqlite3_open16() and the corresponding
        database will by closed.

        SQLITE_OK is returned if the close is successful. If there are prepared
        statements that have not been finalized, then SQLITE_BUSY is returned.
        SQLITE_ERROR might be returned if the argument is not a valid connection
        pointer returned by sqlite3_open() or if the connection pointer has been
        closed previously. 

  In source:
        int sqlite3_close(sqlite3 *db){
           HashElem *i;
           int j;

           if( !db ){
             return SQLITE_OK;
           } 
        ...

So, It seem that NULL is valid connection pointer or close of NULL pointer is
always successful.
It would be nice if documentation declares/guarantees sqlite3_close behavior in 
NULL
pointer case.


        Anton Pak