Thanks Keith, that I understand. Thanks also to everyone who contributed to this thread. I’ve learned a lot from it.
________________________________ From: sqlite-users <sqlite-users-boun...@mailinglists.sqlite.org> on behalf of Keith Medcalf <kmedc...@dessus.com> Sent: Monday, April 15, 2019 4:09:02 PM To: SQLite mailing list Subject: Re: [sqlite] Help with sqlite3_value_text sqlite3_value_text and sqlite3_value_bytes will cause the conversion (if required) to UTF-8, and then return the data requested. sqlite3_value_text16 and sqlite3_value_bytes16 will cause the conversion (if required) to UTF-16 and then return the data requested. So if you call sqlite3_value_text AND THEN sqlite3_value_bytes16 your original UTF-8 text pointer will be invalid. (Because the data must be converted to UTF-16 so that you can get the bytes count of that, thus the original UTF-8 no longer exists). If you call only "like for like" functions, then the conversion will only be carried out the first time it is required and not for the subsequent calls to the "other function" that does not require conversion ... --- The fact that there's a Highway to Hell but only a Stairway to Heaven says a lot about anticipated traffic volume. >-----Original Message----- >From: sqlite-users [mailto:sqlite-users- >boun...@mailinglists.sqlite.org] On Behalf Of x >Sent: Monday, 15 April, 2019 04:08 >To: SQLite mailing list >Subject: Re: [sqlite] Help with sqlite3_value_text > >>As long as you use _value_bytes after _text you're fine... so if any >>conversion did take place the value will be right of the last >returned >>string type. > >JD, Could you explain that to me? I’m not sure why any conversion >takes place and, on reading the text below, I would’ve thought it >would be better to call sqlite3_value_bytes first (if it’s called >“subsequently” the pointer returned by sqlite3_value_text “can be >invalidated”). > >Please pay particular attention to the fact that the pointer returned >from sqlite3_value_blob()<https://sqlite.org/c3ref/value_blob.html>, >sqlite3_value_text()<https://sqlite.org/c3ref/value_blob.html>, or >sqlite3_value_text16()<https://sqlite.org/c3ref/value_blob.html> can >be invalidated by a subsequent call to >sqlite3_value_bytes()<https://sqlite.org/c3ref/value_blob.html>, >sqlite3_value_bytes16()<https://sqlite.org/c3ref/value_blob.html>, >sqlite3_value_text()<https://sqlite.org/c3ref/value_blob.html>, or >sqlite3_value_text16()<https://sqlite.org/c3ref/value_blob.html>.” > > >_______________________________________________ >sqlite-users mailing list >sqlite-users@mailinglists.sqlite.org >http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
