Re: accessing SQLite from root/cint

Hi Philippe,

Many thanks for your help, I will try the sample code later.

In the mean time I have switched to using the more explicit sqlite3_prepare/step/column_* method.

All the best :)
f.

Philippe Canal wrote:
> Hi Fred,
>
> The call back function that you pass back to SQL lite have to be compiled
> they can not be interpreted (at least not directly).
>
> If you really want to an interpreted call back you should compiled a small
> real callback function look like (or any other variant):
>
>
> static int compiled_callback(void *NotUsed, int argc, char **argv, char
> **azColName) {
> gROOT->ProcessLine(Form("actual_callback(0x%x,%d,0x%x,0x%x);",
> NotUsed,argc,argv,azColName));
> }
>
> and actual_callback can now be an interpreted function but
> you are passing the address of compiled_callback to sqllite.
>
> Cheers,
> Philippe.
>
>
> -----Original Message-----
> From: owner-roottalk_at_pcroot.cern.ch [mailto:owner-roottalk_at_pcroot.cern.ch]
> On Behalf Of Fred L Youhanaie
> Sent: Sunday, May 08, 2005 7:41 PM
> To: roottalk_at_pcroot.cern.ch
> Subject: [ROOT] accessing SQLite from root/cint
>
>
> Hi,
>
> I'm trying to use the SQLite API from root directly using the mechanism
> mentioned at: http://root.cern.ch/root/roottalk/roottalk05/0277.html,
> but getting segfaults from cint when sqlite3_exec is called with a
> callback function, an example code is included at the end. I do not get
> segfault when the 'callback' is replaced with 'NULL' when calling
> sqlite3_exec.
>
> The same code (minus cint extern feature) works OK when compiled with
> g++ or ACLiC.
>
> I am using the prebuilt binaries for Linux FC2, 4.03.02 and 4.04.02.
>
> Many thanks and regards
> f.
>
> ==========================================
> #include <stdio.h>
> extern "/opt/sqlite-3.2.1/lib/libsqlite3.so" {
> #pragma preprocessor on
> #include <sqlite3.h>
> #pragma preprocessor off
> };
>
> static int callback(void *NotUsed, int argc, char **argv, char
> **azColName) {
> printf("callback: %d %d\n", (int)NotUsed, argc);
> for (int i=0; i<argc; i++) {
> printf("\t%s=%s\n", azColName[i], argv[i]);
> }
> return 0;
> }
>
> int prog_root()
> {
> sqlite3 *db;
> char *zErrMsg = 0;
> int rc;
> rc = sqlite3_open("test1.db", &db);
> fprintf(stderr, "sqlite3_open: rc=%d.\n", rc);
> if (rc) {
> fprintf(stderr, "Can't open database: %s\n",
> sqlite3_errmsg(db));
> return(1);
> }
> rc = sqlite3_exec(db, "SELECT * FROM tab1", callback, 0, &zErrMsg);
> fprintf(stderr, "sqlite3_exec: rc=%d.\n", rc);
> if (rc) {
> fprintf(stderr, "SQL error: %s\n", zErrMsg);
> }
> rc = sqlite3_close(db);
> fprintf(stderr, "sqlite3_close: rc=%d.\n", rc);
> return(rc);
> }
> ==========================================
>
>
Received on Thu May 12 2005 - 17:56:48 MEST