C-ctypes.h-APIs

API name	API description
isalnum	test for an alphanumeric character
isalpha	test for an alphabetic character
isascii	test for a 7-bit US-ASCII character
isblank	test for a blank character
iscntrl	test for a control character
isdigit	test for a decimal digit
isgraph	test for a visible character
islower	test for a lowercase letter
isprint	test for a printable character
ispunct	test for a punctuation character
isspace	test for a white-space character
isupper	test for an uppercase letter
isxdigit	test for a hexadecimal digit
isalnum_l	test for an alphanumeric character
isalpha_l	test for an alphabetic character
isblank_l	test for a blank character
iscntrl_l	test for a control character
isdigit_l	test for a decimal digit
isgraph_l	test for a visible character
islower_l	test for a lowercase letter
isprint_l	test for a printable character
ispunct_l	test for a punctuation character
isspace_l	test for a white-space character
isupper_l	test for an uppercase letter
isxdigit_l	test for a hexadecimal digit