the published Unicode rules; otherwise, it uses the C library function that
gives the named classification. For example, C<isDIGIT_LC()> when not in a
UTF-8 locale returns the result of calling C<isdigit()>. FALSE is always
-returned if the input won't fit into an octet.
+returned if the input won't fit into an octet. On some platforms where the C
+library function is known to be defective, Perl changes its result to follow
+the POSIX standard's rules.
Variant C<isFOO_LC_uvchr> is like C<isFOO_LC>, but is defined on any UV. It
returns the same as C<isFOO_LC> for input code points less than 256, and
alphanumeric.
See the L<top of this section|/Character classification> for an explanation of
variants
-C<isWORDCHAR_A>, C<isWORDCHAR_L1>, C<isWORDCHAR_uni>, C<isWORDCHAR_utf8>,
-C<isWORDCHAR_LC>, C<isWORDCHAR_LC_uvchr>, and C<isWORDCHAR_LC_utf8>.
+C<isWORDCHAR_A>, C<isWORDCHAR_L1>, C<isWORDCHAR_uni>, and C<isWORDCHAR_utf8>.
+C<isWORDCHAR_LC>, C<isWORDCHAR_LC_uvchr>, and C<isWORDCHAR_LC_utf8> are also as
+described there, but additionally include the platform's native underscore.
=for apidoc Am|bool|isXDIGIT|char ch
Returns a boolean indicating whether the specified character is a hexadecimal
# define _CC_QUOTEMETA 21
# define _CC_NON_FINAL_FOLD 22
# define _CC_IS_IN_SOME_FOLD 23
-/* Unused: 24-31
+# define _CC_MNEMONIC_CNTRL 24
+/* Unused: 25-31
* If more bits are needed, one could add a second word for non-64bit
* QUAD_IS_INT systems, using some #ifdefs to distinguish between having a 2nd
* word or not. The IS_IN_SOME_FOLD bit is the most easily expendable, as it
_generic_isCC(c, _CC_NON_FINAL_FOLD)
# define _IS_IN_SOME_FOLD_ONLY_FOR_USE_BY_REGCOMP_DOT_C(c) \
_generic_isCC(c, _CC_IS_IN_SOME_FOLD)
+# define _IS_MNEMONIC_CNTRL_ONLY_FOR_USE_BY_REGCOMP_DOT_C(c) \
+ _generic_isCC(c, _CC_MNEMONIC_CNTRL)
#else /* else we don't have perl.h */
/* If we don't have perl.h, we are compiling a utility program. Below we