The user would be expected to set up an appropriate search path via the native OS' shared library loading mechanism (PATH, LD_LIBRARY_PATH, or equivalent). These extension shared libraries would not have paths or file suffixes (.dll or. An sqlite specific table in each database loaded could be consulted with a list of shared library names to load. This would benefit SQLite users who do not use the SQLite shell program, and only use the sqlite3 shared library.
#SQLITE DATABASE EXTENSION CODE#
untar latest sqlite3 source code in a new directoryġ.
#SQLITE DATABASE EXTENSION HOW TO#
How To Build a Loadable Extension Shared Library on LinuxĠ. The simplest approach is just to use them as shown above. Header file to find out exactly what they do, if you are curious. You can look at the definitions of these macros in the sqlite3ext.h Through the function pointers in sqlite3_api_routines structure. The SQLITE_EXTENSION_INIT1 and SQLITE3_EXTENSION_INIT2 symbolsĪre C preprocessor macros that deal with redirecting the API routines Loaded module, the you will need to use #ifdefs to #include the Want your code to work as either a statically linked or a dynamically Linked additions to the library should use "sqlite3.h". Loaded extensions should always use "sqlite3ext.h" and statically Note that the extension uses the header file "sqlite3ext.h" We expect that typically extensions willĬreate multiple user functions, collating sequences, and/or virtual-table Loadable extension would probably do something more useful.Ī extension is not limited to creating a single function orĬollating sequence. That multiplies its input by 0.5 is shown. The blue text is code you add to implement your extension. In the example above, the green text is boiler-plate that should Sqlite3_create_function(db, "half", 1, SQLITE_ANY, 0, halfFunc, 0, 0) This is usually the only exported symbol in ** Create new functions, collating sequences, and virtual table * SQLite invokes this routine once when it loads the extension. Sqlite3_result_double(context, 0.5*sqlite3_value_double(argv)) ** The half() SQL function returns half of its input value. The following code is an example of how to build a loadable extension: Newer version of SQLite it will not open a potential exploit. Loading is off by default so that if an older program links against a SQL to do so safely by first turning off extension loading. This allows programs that want to run user-entered The onoff parameter is true to enable extension loading andįalse to disable it. Int sqlite3_enable_load_extension(sqlite3 *db, int onoff) ToĮnable the extension loading mechanism, first invoke this API: The entire extension loading mechanism is turned off by default. This protection and open holes in legacy applications. The new load_extension() SQL function described above could circumvent Sqlite3_set_authorizer() to prevent attacks against the program. Some programs allow users to enter SQL statements then check those
The pApi argument contains pointers back to all of the APIs
To generate an error message and store that message at *pzErrMsg. If an error occurs and pzErrMsg is not NULL, then the extension The extension will likely want to pass this argument through The db parameter is the database connection pointer returned Sqlite3 *db, /* The database connection */Ĭhar **pzErrMsg, /* Write error messages here */Ĭonst sqlite3_api_routines *pApi /* API methods */ The entry point must be a function with the following prototype: If the entry point is omitted then a default entry point function Is the name of an initialization function within the shared library. The filename is the name of the shared library or DLL. SELECT load_extension(' filename ',' entrypoint ') The new API can also be accessed from SQL using the load_extension() The new API is accessed from the shell using the We reserve the right to make changes to the interface.Īfter gaining some experience with the interface, we will probably Not guaranteed to be supported in future releases in a backwardsĬompatible way. This API is experimental meaning that it is There is a new experimental API call sqlite3_load_extension() This means that you no longer have to recompile SQLite in order to add
New SQL functions and collating sequences from shared libraries and DLLs. Beginning after version 3.3.6, SQLite has the ability to load
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