SQLite 用户自定义函数举例

#include  
#include  
#include  
#include  
#include  
#include  
#include #define SELECT_QUERY "SELECT host_id, geturl(desc) FROM host_table; 
void host2url_func( sqlite3_context * ctx, int argc, sqlite3_value ** argv ) 
{ 
　if ( argc != 1 ) return; 
　char * httpurl = NULL; 
　switch( sqlite3_value_type( argv[ 0 ] ) ) 
　{ 
　 case SQLITE_NULL: 
　 { 
　　sqlite3_result_text( ctx, "NULL", 4, SQLITE_STATIC ); 
　　break; 
　 } 
　 case SQLITE_TEXT: 
　 { 
　　httpurl = ( char * ) malloc( strlen( sqlite3_value_text( argv[0] ) ) + 8 ); 
　　if ( httpurl == 0 ) return; 
　　sprintf( httpurl, "http://%s", sqlite3_value_text( argv[ 0 ] ) ); 
　　sqlite3_result_text( ctx, httpurl, strlen( httpurl ), SQLITE_TRANSIENT ); 
　　free( httpurl ); 
　　httpurl = NULL; 
　　break; 
　 } 
　 default: 
　　sqlite3_result_text( ctx, "about:blank", 11, SQLITE_STATIC ); 
　} 
} 
static int callback(void *NotUsed, int argc, char **argv, char **azColName) 
{ 
　 int i; 
　 for(i=0; i