isalnum |
ASCII characters A-Z, a-z and 0-9 |
isalpha |
ASCII characters A-Z and a-z, plus locale-specific single-byte letters |
iscntrl |
ASCII characters with value 0-31 and 127 |
islower |
ASCII characters a-z |
isprint |
Locale-specific single-byte printable characters |
isupper |
ASCII characters A-Z |