“headers already sent” message, issue in WordPress plugin

开发者_运维技巧

I have created a WordPress plugin. while i am going to activate the plugin facing following error:

The plugin generated 250 characters of unexpected output during activation. If you notice “headers already sent” messages, problems with syndication feeds or other issues, try deactivating or removing this plugin.

I have checked for white spaces and characters before the PHP starting tag and closing tag. But error remains.

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Try to remove all comment lines and fill the white spaces in the entire program code. This may help.

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You remove the php close tag ( ?> ) from end of every file ;

when you activate the plugin just check if table already exist or not .

i remove the issue by the code

    if($wpdb->get_var("SHOW TABLES LIKE '$table_name'") != $table_name) {

        $sql = "CREATE TABLE {$table_name}(
            id INT NOT NULL AUTO_INCREMENT,
            name VARCHAR(250),
            email VARCHAR(250),
            PRIMARY KEY (id)
        );";
        dbDelta($sql);
    }