tolower

Synopsis

#include <ctype.h>

int tolower(int c);

Status

Implemented

Conformance

IEEE Std 1003.1-2017

Description

The tolower() function has as a domain a type int, the value of which is representable as a unsigned char or the value of EOF.

If the argument has any other value, the behavior is undefined.

If the argument of tolower() represents an uppercase letter, and there exists a corresponding lowercase letter as defined by character type information in the current locale respectively the result shall be the corresponding lowercase letter.

All other arguments in the domain are returned unchanged.

Return value

Upon successful completion, the tolower() function shall return the lowercase letter corresponding to the argument passed, otherwise, they shall return the argument unchanged.

Errors

No errors are defined.

Tests

Tested

Known bugs

None

See Also

  1. Standard library functions
  2. Table of Contents