pdo - 在非对象上调用成员函数prepare（）[复制]

Question

This question already has an answer here:

• Reference: What is variable scope, which variables are accessible from where and what are “undefined variable” errors? 3 answers
• Can I mix MySQL APIs in PHP? 4 answers

This code get an error:

Fatal error: Call to a member function prepare() on a non-object in C:\Users\fel\VertrigoServ\www\login\validation.php on line 42

CODE:

   function repetirDados($email) {
        if(!empty($_POST['email'])) {

            $query = "SELECT email FROM users WHERE email = ?";

            $stmt = $pdo->prepare($query); // error line: line 42

            $email = mysql_real_escape_string($_POST['email']);

            $stmt->bindValue(1, $email);

            $ok = $stmt->execute();

            $results = $stmt->fetchAll(PDO::FETCH_ASSOC);

            if ($results == 0) {
                return true;
            } else {
                echo '<h1>something</h1>';
                return false;
            }
        }
    }

What is the possible cause? Another question, What is the equivalent to mysql_num_rows? sorry, I am newbie with pdo

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Answer 1

$pdo is undefined. You're not declaring it inside the function, and it isn't being passed in as an argument.

You need to either pass it in (good), or define it in the global namespace and make it available to your function by placing global $pdo at the top (bad).