< ?php next_post_link($format='%link »', $link='%title', $in_same_cat
= false, $excluded_categories = 'X and X and X' ); ?>


It’s explained in better detail on the wordpress codex here

As you will no doubt notice, the third parameter ‘$in_same_cat’ is bogus and doesn’t work if set to ‘true.’

I figured out how to submit bug reports:

http://trac.wordpress.org/ticket/4304

There’s a one line fix for WP2.1.3 to get this code to work. In both functions, this line (lines 294 and 331 in link-template.php):

$sql_cat_ids = " OR pc.category_ID = '$category'";

should be changed to

$sql_cat_ids .= " OR pc.category_ID = '$category'";

(changed = to .=)

Where do I submit WP bug reports & fixes. Can I submit a patch myself?

If I use

get_next_post(‘%link’, ‘%title’, FALSE, ‘1 and 2′);

then posts in category 2 are ignored, but not those in 1. It’s quite annoying!

I looked at the code, but at cursory inspection I can’t see what’s wrong with it. Have you managed to get this feature to work in v2.1.3?

Thanks for the “hack” – it really works like a charm and has been ever since I implemented the Sideblog plugin on top of WP2.03. Would you know whether the faulty core code has been fixed in WP2.1?

Thanks,
Oliver

Thanks for this fix man. It was just what I was looking for.

Brance

Whenever I post PHP code (all properly escaped into HTML entities) within a post in Wordpress 2.0.4 I get Error 403 on post.php!

Although it is my first time, it seems to me that people have been posting PHP code snippets forever in Wordpress. Do you have any idea why this might be happening?

It looks like this bug has been fixed for the next release, so it’s safe to apply your hack without upgrade worries.

i’m glad you found this useful. i suspect that the next WP release will (finally!) fix this problem.

i’m not really familiar with the trac solution, but it looks to me like it’s meant to be used with the “patch” command to automatically apply the changes to your files.

Thanks for this. It’s much easier to follow than the current trac solution, which only suggests changes to get_next_post and next_post_link. Did I misunderstand that trac file? I like that it tells me which lines to delete and include, but this solution just seems to make more sense because we alter both the next and previous functions.

btw, it looks like someone else noticed that it’s still broken in 2.0 (and fixed it):

http://wordpress.org/support/topic/44031?replies=11

so, pretty soon, my hack will become obsolete.

Your fix still works with version 2.0, thanks again.

– Your ever greatful WordPress fan, Arthur.

to restate what i think you said: you found that the deprecated functions next_post() and previous_post() both do correctly exclude categories, so if someone is using those functions then they need not apply the hack i outlined above. (and just so people know, it looks from your blog like you’re talking about WP version 1.5.2 here.)

this info will surely help some people out, but i would also advise some caution. if the codex states that the parameter is “archaic,” then its behaviour–across future releases–is tenuous at best (and undefined at worst).

in any case, i hope this is fixed in 1.6. i’ll be happy to retire this blog entry.

p.s., i’m going to add a note beneath the code snippet to help people avoid the copy&paste trouble you just had.

Okay, now I’ll heap all the richly deserved praise upon you, Ron. AWESOME!

True, my “=” -> “.=” was pure desperation — but I did manage to hunt down the code problem:

when cutting & pasting from the above box, the

$sql_exclude_cats .= ',' . intval($excluded_post_rows[$i]->post_
id);

(which is forced onto two lines) inserts a CRLF between “_” and “id”, which understandably [m]ucks up the works. By backspacing the “id” back onto the “post_”, everything started working hunky-dory.

As to the hebrew error message, I’ve always been disgusted by accusations of some shadowy international zionist conspiracy, but now I’m not so sure… .

Thanks again, Ron.

i’ll try to help… hopefully we can get it working for you.

a few things:

1. oops, sorry about the "’s. i’ve edited the entry and fixed them above. (by way of explanation, they were there because of a code-formatting plug-in that i installed after i wrote this entry.)

2. i think your change of “=” to “.=” was an error (albeit a harmless one). it should in fact be a straight assignment there, not a concatenation.

would you mind trying one more time to copy & paste the (fixed) code into your installation from scratch?

if you still see the problem, write back and include how you’re calling next_post_link(). also, let me know if it doesn’t work for both next_post_link and prev_post_link, since there’s the outside possibility (because of all the manual editing required) that it ends up working for one of them but not the other.

(and if the problem is solved, then let me know that too. )

p.s., i find it odd that your php installation is giving you error messages in hebrew (PAAMAYIM NEKUDOTAYIM).

Can’t get this to work. I’ve tried the version above and the one on the wordpress forum — I get this error:

Parse error: parse error, unexpected ‘;’, expecting T_PAAMAYIM_NEKUDOTAYIM or ‘(‘ in /home/jump1932/public_html/wp/wp-includes/template-functions-links.php on line 260

After replacing all the & quot; and replacing

$sql_exclude_cats =
' AND ID NOT IN ('

with

$sql_exclude_cats .=
' AND ID NOT IN ('

I got the site to load without error, but there still seems to be no functionality. I’m trying to hide my category “9″. Note: I did put the appropriate declarations in the next_post_link().

Any ideas?

Sara said:

Why does the sql exclude cats? I think that’s just plain mean.

even though i laughed out loud at your comment, you’re still in trouble. (along with that “Ferritis” character.)

thanks for the comment–i’m so happy that this was actually helpful to someone! (and now maybe my wisecracking, non-techie friends will keep their traps shut ).

and extra thanks for pointing out the cut/paste problem! i’ve fixed the code snippet. (though i had to settle for inferior double quotes since i couldn’t quickly figure out how to escape the php code in WordPress. )

enjoy!

Ron, thank you so much for this solution! I just changed my template-function-links.php file, and it works perfectly! I’ve been looking for a solution for this for several weeks now, and I had just about given up when I saw your posting at wordpress.org/support. This is exactly what I need, and I very much appreciate your implementing it.

One point about the code in html that you have posted above: the last line that reads $sql_exclude_cats .= ‘)’; actually uses curly single quotes, ie: the html code shows the entities ‘ and ’ which may confuse those who are cutting and pasting from this page.

Ron, thank you again. I’m an HTML/JavaScript sort of guy who is completely lost in the world of PHP and SQL. Please let me know if there is anything I can ever do for you!

– Arthur