PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of this interface
       may differ (consult the corresponding Linux manual page for details of Linux behavior), or the  interface
       may not be implemented on Linux.

NAME

       tolower, tolower_l — transliterate uppercase characters to lowercase

SYNOPSIS

       #include <ctype.h>

       int tolower(int c);
       int tolower_l(int c, locale_t locale);

DESCRIPTION

       For tolower(): The functionality described on this reference page is aligned with the ISO C standard. Any
       conflict between the requirements described here and the ISO C standard is unintentional. This volume  of
       POSIX.1‐2008 defers to the ISO C standard.

       The  tolower() and tolower_l() functions have 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 behavior is  undefined.
       If  the  argument  of  tolower()  or  tolower_l()  represents  an  uppercase  letter,  and there exists a
       corresponding lowercase letter as defined by character type information in the current locale or  in  the
       locale  represented  by  locale,  respectively (category LC_CTYPE), the result shall be the corresponding
       lowercase letter. All other arguments in the domain are returned unchanged.

       The behavior  is  undefined  if  the  locale  argument  to  tolower_l()  is  the  special  locale  object
       LC_GLOBAL_LOCALE or is not a valid locale object handle.

RETURN VALUE

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

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       setlocale(), uselocale()

       The Base Definitions volume of POSIX.1‐2008, Chapter 7, Locale, <ctype.h>, <locale.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
       Standard  for  Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers,  Inc
       and  The  Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the event
       of any discrepancy between this version and the original IEEE and The Open Group Standard,  the  original
       IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at
       http://www.unix.org/online.html .

       Any typographical or formatting errors that appear in this page are most likely to have  been  introduced
       during   the   conversion  of  the  source  files  to  man  page  format.  To  report  such  errors,  see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .