-The \c facility was designed for use with ASCII characters, but with the
-extension to Unicode it is even less useful than it once was. It is, however,
-recognized when PCRE is compiled in EBCDIC mode, where data items are always
-bytes. In this mode, all values are valid after \c. If the next character is a
-lower case letter, it is converted to upper case. Then the 0xc0 bits of the
-byte are inverted. Thus \cA becomes hex 01, as in ASCII (A is C1), but because
-the EBCDIC letters are disjoint, \cZ becomes hex 29 (Z is E9), and other
-characters also generate different values.
+When PCRE is compiled in EBCDIC mode, \a, \e, \f, \n, \r, and \t
+generate the appropriate EBCDIC code values. The \c escape is processed
+as specified for Perl in the <b>perlebcdic</b> document. The only characters
+that are allowed after \c are A-Z, a-z, or one of @, [, \, ], ^, _, or ?. Any
+other character provokes a compile-time error. The sequence \@ encodes
+character code 0; the letters (in either case) encode characters 1-26 (hex 01
+to hex 1A); [, \, ], ^, and _ encode characters 27-31 (hex 1B to hex 1F), and
+\? becomes either 255 (hex FF) or 95 (hex 5F).
+</P>
+<P>
+Thus, apart from \?, these escapes generate the same character code values as
+they do in an ASCII environment, though the meanings of the values mostly
+differ. For example, \G always generates code value 7, which is BEL in ASCII
+but DEL in EBCDIC.
+</P>
+<P>
+The sequence \? generates DEL (127, hex 7F) in an ASCII environment, but
+because 127 is not a control character in EBCDIC, Perl makes it generate the
+APC character. Unfortunately, there are several variants of EBCDIC. In most of
+them the APC character has the value 255 (hex FF), but in the one Perl calls
+POSIX-BC its value is 95 (hex 5F). If certain other characters have POSIX-BC
+values, PCRE makes \? generate 95; otherwise it generates 255.