1TOLOWER(3P)                POSIX Programmer's Manual               TOLOWER(3P)
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PROLOG

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

12       tolower, tolower_l — transliterate uppercase characters to lowercase
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SYNOPSIS

15       #include <ctype.h>
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17       int tolower(int c);
18       int tolower_l(int c, locale_t locale);
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DESCRIPTION

21       For tolower(): The functionality described on this  reference  page  is
22       aligned  with the ISO C standard. Any conflict between the requirements
23       described here and the ISO C standard is unintentional. This volume  of
24       POSIX.1‐2017 defers to the ISO C standard.
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26       The  tolower()  and  tolower_l() functions have as a domain a type int,
27       the value of which is representable as an unsigned char or the value of
28       EOF. If the argument has any other value, the behavior is undefined. If
29       the argument of tolower() or tolower_l() represents an  uppercase  let‐
30       ter,  and  there  exists a corresponding lowercase letter as defined by
31       character type information in the current locale or in the locale  rep‐
32       resented  by locale, respectively (category LC_CTYPE), the result shall
33       be the corresponding lowercase  letter.  All  other  arguments  in  the
34       domain are returned unchanged.
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36       The  behavior is undefined if the locale argument to tolower_l() is the
37       special locale object LC_GLOBAL_LOCALE or is not a valid locale  object
38       handle.
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RETURN VALUE

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

46       No errors are defined.
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48       The following sections are informative.
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EXAMPLES

51       None.
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APPLICATION USAGE

54       None.
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RATIONALE

57       None.
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FUTURE DIRECTIONS

60       None.
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SEE ALSO

63       setlocale(), uselocale()
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65       The  Base  Definitions  volume  of  POSIX.1‐2017,  Chapter  7,  Locale,
66       <ctype.h>, <locale.h>
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69       Portions of this text are reprinted and reproduced in  electronic  form
70       from  IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
71       table Operating System Interface (POSIX), The Open Group Base  Specifi‐
72       cations  Issue  7, 2018 Edition, Copyright (C) 2018 by the Institute of
73       Electrical and Electronics Engineers, Inc and The Open Group.   In  the
74       event of any discrepancy between this version and the original IEEE and
75       The Open Group Standard, the original IEEE and The Open Group  Standard
76       is  the  referee document. The original Standard can be obtained online
77       at http://www.opengroup.org/unix/online.html .
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79       Any typographical or formatting errors that appear  in  this  page  are
80       most likely to have been introduced during the conversion of the source
81       files to man page format. To report such errors,  see  https://www.ker
82       nel.org/doc/man-pages/reporting_bugs.html .
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86IEEE/The Open Group                  2017                          TOLOWER(3P)
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