ISWLOWER (man3p)
iswlower, iswlower_l — test for a lowercase letter wide-character code
iswlower, iswlower_l — test for a lowercase letter wide-character code
iswupper, iswupper_l — test for an uppercase letter wide-character code
fopen — open a stream
msgrcv — XSI message receive operation
fesetexceptflag — set floating-point status flags
iswxdigit, iswxdigit_l — test for a hexadecimal digit wide-character code
shutdown — shut down socket send and receive operations
catclose — close a message catalog descriptor
alarm — schedule an alarm signal
environ — array of character pointers to the environment strings