mysqli_stmt_bind_param causes fatal error: memory size exhausted

Question

I thought this was a quite simple query:

$qry="SELECT taglink, tagtitle, tagshow FROM taglist_main WHERE tag = ?";
if ($stmt = mysqli_prepare($link,$qry)) {
    mysqli_stmt_bind_param($stmt,"s",$qstring);
    mysqli_stmt_execute($stmt);
    mysqli_stmt_bind_result($stmt,$taglink,$tagtitle,$tagshow);
    mysqli_stmt_store_result($stmt);
    echo "<p><strong>".mysqli_stmt_num_rows($stmt)."</strong> entries found, shown below.</p>";                         
    while (mysqli_stmt_fetch($stmt)) {
        echo "<li><a href=\"/$taguri\" title=\"$tagtitle\">$tagshow</a></li>";
    }
mysqli_stmt_close($stmt);

However, php seems to think otherwise. When running the query, I got the following error:

Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 4294967296 bytes) in /home/envoyenv/public_html/envoytest/tags/index.php on line 110

when using the mysql_stmt_bind_param line. If I leave that line out and adjust the SELECT statement to use the string variable $qstring directly, I get no results shown on screen (actually, I get NOTHING shown on screen, not even the echo!)

This isn't a particularly large table (less than 300 rows) and this query should return 10 rows or so (and the SELECT statement works fine in phpmyadmin, the expected results are returned)

What am I doing wrong?

---

Edit:

I'd already checked to ensure $qstring was actually a string: here's the result of var_dump: string(14) "riskassessment"

Answer 1

With help from @andrewsi:

Swap the order of the mysqli_stmt_bind_result($stmt,$taglink,$tagtitle,$tagshow); and mysqli_stmt_store_result($stmt); lines so the code fragment now reads:

$qry="SELECT taglink, tagtitle, tagshow FROM taglist_main WHERE tag = ?";
if ($stmt = mysqli_prepare($link,$qry)) {
    mysqli_stmt_bind_param($stmt,"s",$qstring);
    mysqli_stmt_execute($stmt);
    mysqli_stmt_store_result($stmt);
    mysqli_stmt_bind_result($stmt,$taglink,$tagtitle,$tagshow);
    echo "<p><strong>".mysqli_stmt_num_rows($stmt)."</strong> entries found, shown below.</p>";                         
    while (mysqli_stmt_fetch($stmt)) {
        echo "<li><a href=\"/$taguri\" title=\"$tagtitle\">$tagshow</a></li>";
    }
mysqli_stmt_close($stmt);

Hopefully this will be useful for those who still like to write procedural code.