RE: [PHP-DEV] when to duplicate string using add_index_string?
I'm using add_index_string and add_assoc_string to build an array, and
these
functions expect a 'duplicate' argument. When should I set this to 1 and
when to 0?
First of all, it definitely matters. Sending the right value is extremely
important. If you send 1 instead of 0, then you would get a memory
leak. If you send a 0 instead of 1, you'll most likely crash. So you
really must send the right values each time :)
[...]
So what you're saying is
- if duplicate is set to 0, you create a reference
- if duplicate is set to 1, you increase the reference counter
so that 'duplicate' means 'I am a duplicate', instead of what I first
thought 'duplicate me' (which is why I sent a 1 first (duplicate me), and a
0 second).
OK, that's clear now.
Another question that's related to this: Am I right when I say:
when I have created and initialized a zval in a function (MAKE_STD_ZVAL) I
should also free it in this function (FREE_ZVAL), except when I add it
directly to the hashtable (zend_hash_index_update), because then it is freed
automatically?
The following code-snippet from a function (dbx_query) actually works and
doesn't crash or leak, based on this assumption
// fill each row array with fieldvalues (indexed and assoc)
row_count=0;
result=1;
while (result) {
zval * rv_row;
MAKE_STD_ZVAL(rv_row);
result = switch_dbx_getrow(rv_row, rv_result_handle,
DBX_RESULT_INDEX | DBX_RESULT_ASSOC, INTERNAL_FUNCTION_PARAM_PASSTHRU,
dbx_module);
if (result) {
zend_hash_index_update(data-value.ht, row_count, (void
*)(rv_row), sizeof(zval *), NULL);
++row_count;
}
else {
FREE_ZVAL(rv_row);
}
}
And yes, as you have guessed, I've started on creating a database
abstraction module :-)
It is called 'dbx' and currently already works for mysql...
Since I want this Open Source'd (and preferably in the php-cvs-tree as
well), how would I go about doing that (this will be my first open source
code)?
Thanks, Marc.
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RE: [PHP-DEV] when to duplicate string using add_index_string?
At 15:51 8/2/2001, Marc Boeren wrote: I'm using add_index_string and add_assoc_string to build an array, and these functions expect a 'duplicate' argument. When should I set this to 1 and when to 0? First of all, it definitely matters. Sending the right value is extremely important. If you send 1 instead of 0, then you would get a memory leak. If you send a 0 instead of 1, you'll most likely crash. So you really must send the right values each time :) [...] So what you're saying is - if duplicate is set to 0, you create a reference - if duplicate is set to 1, you increase the reference counter so that 'duplicate' means 'I am a duplicate', instead of what I first thought 'duplicate me' (which is why I sent a 1 first (duplicate me), and a 0 second). No, it's not clear I guess :) 'duplicate' does mean 'duplicate me'. If duplicate is set to 0, then you tell the engine not to duplicate the string, but use it as-is. If it's set to 1, then you tell the engine to duplicate it, because this string is either static, or already referenced by other things in PHP. Zeev -- PHP Development Mailing List http://www.php.net/ To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] To contact the list administrators, e-mail: [EMAIL PROTECTED]
Re: [PHP-DEV] when to duplicate string using add_index_string?
On Thu, Feb 08, 2001 at 03:45:33PM +0200, Zeev Suraski wrote: First of all, it definitely matters. Sending the right value is extremely important. If you send 1 instead of 0, then you would get a memory leak. If you send a 0 instead of 1, you'll most likely crash. So you really must send the right values each time :) [...] So what you're saying is - if duplicate is set to 0, you create a reference - if duplicate is set to 1, you increase the reference counter so that 'duplicate' means 'I am a duplicate', instead of what I first thought 'duplicate me' (which is why I sent a 1 first (duplicate me), and a 0 second). No, it's not clear I guess :) 'duplicate' does mean 'duplicate me'. If duplicate is set to 0, then you tell the engine not to duplicate the string, but use it as-is. If it's set to 1, then you tell the engine to duplicate it, because this string is either static, or already referenced by other things in PHP. Perhaps 0 and 1 should be replaced by more verbose #define's (constants) to make this code clearer, then. -- Jon Parise ([EMAIL PROTECTED]) . Rochester Inst. of Technology http://www.csh.rit.edu/~jon/ : Computer Science House Member -- PHP Development Mailing List http://www.php.net/ To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] To contact the list administrators, e-mail: [EMAIL PROTECTED]
