sqlite3_result_int, we must first find out which place its function pointer occupies in said array. In C, macros take care of making them convenient to call, but in Xojo it means a bit more work for us.īasically, to call a function, e.g. For this, sqlite provides a large set of functions through its API. The problem is: While it's fairly easy to invoke them from C code, it's rather tedious to do in Xojo, because they're accessed through an array of function pointers (note the pApi parameter the sqlite3_extension_init gets passed - that's where all those pointers are located). Our custom function certainly wants to be able to receive parameters, return values and maybe even perform database access operations on its own. How that's done is documented in the SQLite docs.
Xojo 2015r2 registration#
Once the extension gets loaded and our callback function gets called, we perform the registration of the custom functions.
Xojo 2015r2 portable#
(This code should be portable for Windows and Linux as well - the actual source code contains some extra instructions for Windows DLLs). Its code then invokes our previously set Xojo function through the stored callback function pointer. Then, once we load this extension using the "SELECT load_extension" command, sqlite3_extension_init will get called. The SetCallback function stores the address of our Xojo function for later use. We pass it the address of a Xojo function in which we'll handle the installation of our custom functions. This is a function we'll call from Xojo before loading this extension into the sqlite engine. The first relevant part here is the SetCallback function. so files of the ICU-sqlite lib on the web and use them with these instructions. I believe, however, that you can more easily find. Mind you, only for OS X, though, as I do not have the time to make and test versions for Windows and Linux as well. Therefore, I'm making my own built version available, along with the source code. And unfortunately, there is none publically available as far as I could see, at least not for OS X. Still, you need to have a readily built ICU lib for sqlite before you can load it. Furtunately, though, Xojo's plugin allows dynamic loading of extensions (like plugins) into the sqlite engine. This is not a viable option with Xojo because you'd also have to write your own Database plugin to make the sqlite lib usable in Xojo (while the sqlite lib is open source, Xojo's plugin is not, or this would be less of an issue). The usual solution to this is to compile the sqlite3 library with ICU support and then include this lib in your program. This missing unicode support also affects sorting and related comparison functions. only the plain ASCII chars (a-z) will get uppercased but not the special french chars. For instance, if you try to use the SQL function upper on a french phrase such as Tête-à-Tête, you will get TêTE-à-TêTE, i.e. Xojo's default Database class REALSQLDatabase (or its replacement SQLiteDatabase), which is based on sqlite, does not support international (non-english) characters.
0 kommentar(er)
