samplext.c

来自「SQLite ODBC Driver SQLite3 的ODBC驱动」· C语言 代码 · 共 40 行

/*
 * SQLite3 example extension from wiki
 * http://www.sqlite.org/cvstrac/wiki?p=LoadableExtensions
 *
 * Compile with
 *   tcc -rdynamic -shared -o samplext.dll samplext.c
 */

#include <sqlite3ext.h>

SQLITE_EXTENSION_INIT1

/*
 * The half() SQL function returns half of its input value.
 */
static void halfFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  sqlite3_result_double(context, 0.5 * sqlite3_value_double(argv[0]));
}

/*
 * SQLite invokes this routine once when it loads the extension.
 * Create new functions, collating sequences, and virtual table
 * modules here.  This is usually the only exported symbol in
 * the shared library.
 */
int sqlite3_extension_init(
  sqlite3 *db,
  char **pzErrMsg,
  const sqlite3_api_routines *pApi
){
  SQLITE_EXTENSION_INIT2(pApi)
  sqlite3_create_function(db, "half", 1, SQLITE_ANY, 0, halfFunc, 0, 0);
  return 0;
}