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Character Routines

Routine Attributes Description
isalnum reentrant Tests for an alphanumeric character.
isalpha reentrant Tests for an alphabetic character.
iscntrl reentrant Tests for a Control character.
isdigit reentrant Tests for a decimal digit.
isgraph reentrant Tests for a printable character with the exception of space.
islower reentrant Tests for a lowercase alphabetic character.
isprint reentrant Tests for a printable character.
ispunct reentrant Tests for a punctuation character.
isspace reentrant Tests for a whitespace character.
isupper reentrant Tests for an uppercase alphabetic character.
isxdigit reentrant Tests for a hexadecimal digit.
toascii reentrant Converts a character to an ASCII code.
toint reentrant Converts a hexadecimal digit to a decimal value.
tolower reentrant Tests a character and converts it to lowercase if it is uppercase.
_tolower reentrant Unconditionally converts a character to lowercase.
toupper reentrant Tests a character and converts it to uppercase if it is lowercase.
_toupper reentrant Unconditionally converts a character to uppercase.

The character routines allow you to test individual characters for a variety of attributes and convert characters to different formats.

The _tolower, _toupper, and toascii routines are implemented as macros. All other routines are implemented as functions. All macro definitions and function prototypes are found in the ctype.h include file.

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