tolower(3p) — Linux manual page

TOLOWER(3P)             POSIX Programmer's Manual            TOLOWER(3P)

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.1‐2017 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(3p), uselocale(3p)

       The Base Definitions volume of POSIX.1‐2017, Chapter 7, Locale,
       ctype.h(0p), locale.h(0p)

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 by the Institute of Electrical and Electronics
       Engineers, Inc and The Open Group.  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.opengroup.org/unix/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 .

IEEE/The Open Group               2017                       TOLOWER(3P)

Pages that refer to this page: ctype.h(0p), setlocale(3p), _tolower(3p)

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