Boost C++ Libraries

alnum

Yes

Any alpha-numeric character.

alpha

Yes

Any alphabetic character.

blank

Yes

Any whitespace character that is not a line separator.

cntrl

Yes

Any control character.

d

No

Any decimal digit

digit

Yes

Any decimal digit.

graph

Yes

Any graphical character.

l

No

Any lower case character.

lower

Yes

Any lower case character.

print

Yes

Any printable character.

punct

Yes

Any punctuation character.

s

No

Any whitespace character.

space

Yes

Any whitespace character.

unicode

No

Any extended character whose code point is above 255 in value.

u

No

Any upper case character.

upper

Yes

Any upper case character.

w

No

Any word character (alphanumeric characters plus the underscore).

word

No

Any word character (alphanumeric characters plus the underscore).

xdigit

Yes

Any hexadecimal digit character.