ob_start（）使用用户定义的函数内部出错

Question

function d() {
            return "from d output
";

        }
        ob_start();
        //var_dump("any thing
");
        d();
        $a= ob_get_clean();
        echo "$a";

i'm starting doing things in php. I've used this code but in this case no output is being printed to the browser. But whenever I'm using code likevar_dump("anything "); within the two ob_ block I'm getting output. My question is what is the difference between the output of var_dump() and my handwritten function d() in this case?

Answer 1

Change this:

d();

... into this:

echo d();

Invoking a function does not automatically print its return value. Or, if you want to mimic var_dump()'s behaviour:

function d() {
    echo "from d output
";
}