const char *sqlite3_filename_database(const char*); const char *sqlite3_filename_journal(const char*); const char *sqlite3_filename_wal(const char*);
These routines are available to custom VFS implementations for translating filenames between the main database file, the journal file, and the WAL file.
If F is the name of an sqlite database file, journal file, or WAL file passed by the SQLite core into the VFS, then sqlite3_filename_database(F) returns the name of the corresponding database file.
If F is the name of an sqlite database file, journal file, or WAL file passed by the SQLite core into the VFS, or if F is a database filename obtained from sqlite3_db_filename(), then sqlite3_filename_journal(F) returns the name of the corresponding rollback journal file.
If F is the name of an sqlite database file, journal file, or WAL file that was passed by the SQLite core into the VFS, or if F is a database filename obtained from sqlite3_db_filename(), then sqlite3_filename_wal(F) returns the name of the corresponding WAL file.
In all of the above, if F is not the name of a database, journal or WAL filename passed into the VFS from the SQLite core and F is not the return value from sqlite3_db_filename(), then the result is undefined and is likely a memory access violation.