The Open Group Base Specifications Issue 7, 2018 edition
IEEE Std 1003.1-2017 (Revision of IEEE Std 1003.1-2008)
Copyright © 2001-2018 IEEE and The Open Group

NAME

_tolower - transliterate uppercase characters to lowercase

SYNOPSIS

[OB XSI] [Option Start] #include <ctype.h>

int _tolower(int
c); [Option End]

DESCRIPTION

The _tolower() macro shall be equivalent to tolower(c) except that the application shall ensure that the argument c is an uppercase letter.

RETURN VALUE

Upon successful completion, _tolower() shall return the lowercase letter corresponding to the argument passed.

ERRORS

No errors are defined.


The following sections are informative.

EXAMPLES

None.

APPLICATION USAGE

Applications should use the tolower() function instead of the obsolescent _tolower() function.

RATIONALE

None.

FUTURE DIRECTIONS

The _tolower() function may be removed in a future version.

SEE ALSO

tolower, isupper

XBD Locale, <ctype.h>

CHANGE HISTORY

First released in Issue 1. Derived from Issue 1 of the SVID.

Issue 6

The normative text is updated to avoid use of the term "must" for application requirements.

Issue 7

The _tolower() function is marked obsolescent.

End of informative text.

 

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