[string|null$charset = null],
[string|null$transfer_encoding = null],
[string$newline = "\r\n"],
[int$indent = 0]
Encodes a given string string by the MIME header encoding scheme.
The string being encoded. Its encoding should be same as mb_internal_encoding.
charset specifies the name of the character set in which string is represented in. The default value is determined by the current NLS setting (mbstring.language).
transfer_encoding specifies the scheme of MIME encoding. It should be either "B" (Base64) or "Q" (Quoted-Printable). Falls back to "B" if not given.
newline specifies the EOL (end-of-line) marker with which mb_encode_mimeheader performs line-folding (a RFC term, the act of breaking a line longer than a certain length into multiple lines. The length is currently hard-coded to 74 characters). Falls back to "\r\n" (CRLF) if not given.
Indentation of the first line (number of characters in the header before string).
A converted version of the string represented in ASCII.
This function isn't designed to break lines at higher-level contextual break points (word boundaries, etc.). This behaviour may clutter up the original string with unexpected spaces.
|8.0.0||charset and transfer_encoding are nullable now.|