# Character type checking

- Introduction
- Installing/Configuring
  - Requirements
  - Installation
  - Runtime Configuration
  - Resource Types
- Predefined Constants
- Ctype Functions
  - ctype_alnum — Check for alphanumeric character(s)
  - ctype_alpha — Check for alphabetic character(s)
  - ctype_cntrl — Check for control character(s)
  - ctype_digit — Check for numeric character(s)
  - ctype_graph — Check for any printable character(s) except space
  - ctype_lower — Check for lowercase character(s)
  - ctype_print — Check for printable character(s)
  - ctype_punct — Check for any printable character which is not whitespace or an alphanumeric character
  - ctype_space — Check for whitespace character(s)
  - ctype_upper — Check for uppercase character(s)
  - ctype_xdigit — Check for character(s) representing a hexadecimal digit