Re: [sqlite] Extracting values from callback
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Re: [sqlite] Extracting values from callback
Well...
At 22:23 11/5/2004 +0100, you wrote:
I've been trying at this for a good few hours now, I'm using sqlite3 and
the quick start code at the website.
By using a global "char *buffer[5][220];"
and then doing buffer[i][counter]=argv[i]; I thought I would be able to
extract the rows in my table but it does not work. When the program has
exited the callback buffer[i][0] equals buffer[i][1] and so on. For some
reason all of them will have the values of the last callback execution.
What you do not seem to understand is that the strings passed to the
callback function are created (and freed) by SQLite code. You can't keep
pointers to them outside of the callback.
For example, you could print out the values using a code like this:
[snip]
int counter=0;
static int callback(void *NotUsed, int argc, char **argv, char **azColName){
int k;
for(k=0;k
Re: [sqlite] Extracting values from callback
> static int callback(void *NotUsed, int argc, char
> **argv, char **azColName){
> int k;
> rows=argc;
> for(k=0;k {
> buffer[k][counter]= argv[k];
> }
> counter++;
> return 0;
> }
The data pointed to by argv[k] only exists for the
duration of the callback. You have to copy the string,
not the pointer. i.e:
buffer[k][counter] = strdup(argv[k]);
(won't work with blobs). Don't forget to free() it
later.
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[sqlite] Extracting values from callback
I've been trying at this for a good few hours now, I'm using sqlite3 and the
quick start code at the website.
By using a global "char *buffer[5][220];"
and then doing buffer[i][counter]=argv[i]; I thought I would be able to
extract the rows in my table but it does not work. When the program has
exited the callback buffer[i][0] equals buffer[i][1] and so on. For some
reason all of them will have the values of the last callback execution.
int counter=0;
char *buffer[5][220];
int rows;
static int callback(void *NotUsed, int argc, char **argv, char **azColName){
int k;
rows=argc;
for(k=0;k
