man pages section 3: Basic Library Functions

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Updated: July 2014
 
 

tolower(3C)

Name

tolower - transliterate upper-case characters to lower-case

Synopsis

#include <ctype.h> 

int tolower(int c);

Description

The tolower() function has as a domain a type int, the value of which is representable as an unsigned char or the value of EOF. If the argument has any other value, the argument is returned unchanged. If the argument of tolower() represents an upper-case letter, and there exists a corresponding lower-case letter (as defined by character type information in the program locale category LC_CTYPE), the result is the corresponding lower-case letter. All other arguments in the domain are returned unchanged.

Return Values

On successful completion, tolower() returns the lower-case letter corresponding to the argument passed. Otherwise, it returns the argument unchanged.

Errors

No errors are defined.

Attributes

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE
ATTRIBUTE VALUE
CSI
Enabled
Interface Stability
Standard
MT-Level
MT-Safe

See Also

_tolower(3C), setlocale(3C), attributes(5), standards(5)