PHP可以检测Apache是​​否正在发送默认的字符集标题吗？

Question

In the Apache config, one can set the following directive to cause the httpd to always send a UTF-8 character encoding header for text/html and text/plain MIME types:

AddDefaultCharset utf-8

I would like to be able to detect in my PHP scripts whether or not this header is being sent, so that I can send the same header using the header() function if it hasn't been sent.

How can I detect this?

Answer 1

Information provided by deceze in the comments on the initial question negated a need for an answer. However, for the sake of completeness, I would say that it appears that there isn't an obvious way to detect if headers have been sent by Apache from within PHP... but, given the above information, I can't think of a reason why you'd need to.