ctype.h(3)                 POSIX Programmer's Manual                ctype.h(3)



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

NAME
       ctype.h -- character types

SYNOPSIS
       #include <ctype.h>

DESCRIPTION
       Some of the functionality described on this reference page extends the
       ISO C standard. Applications shall define the appropriate feature test
       macro (see the System Interfaces volume of POSIX.1-2017, Section 2.2,
       The Compilation Environment) to enable the visibility of these symbols
       in this header.

       The <ctype.h> header shall define the locale_t type as described in
       <locale.h>, representing a locale object.

       The following shall be declared as functions and may also be defined as
       macros. Function prototypes shall be provided for use with ISO C
       standard compilers.


           int   isalnum(int);
           int   isalnum_l(int, locale_t);
           int   isalpha(int);
           int   isalpha_l(int, locale_t);
           int   isascii(int);
           int   isblank(int);
           int   isblank_l(int, locale_t);
           int   iscntrl(int);
           int   iscntrl_l(int, locale_t);
           int   isdigit(int);
           int   isdigit_l(int, locale_t);
           int   isgraph(int);
           int   isgraph_l(int, locale_t);
           int   islower(int);
           int   islower_l(int, locale_t);
           int   isprint(int);
           int   isprint_l(int, locale_t);
           int   ispunct(int);
           int   ispunct_l(int, locale_t);
           int   isspace(int);
           int   isspace_l(int, locale_t);
           int   isupper(int);
           int   isupper_l(int, locale_t);
           int   isxdigit(int);
           int   isxdigit_l(int, locale_t);
           int   toascii(int);
           int   tolower(int);
           int   tolower_l(int, locale_t);
           int   toupper(int);
           int   toupper_l(int, locale_t);

       The <ctype.h> header shall define the following as macros:


           int   _toupper(int);
           int   _tolower(int);

       The following sections are informative.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       <locale.h>

       The System Interfaces volume of POSIX.1-2017, Section 2.2, The
       Compilation Environment, isalnum(), isalpha(), isascii(), isblank(),
       iscntrl(), isdigit(), isgraph(), islower(), isprint(), ispunct(),
       isspace(), isupper(), isxdigit(), mblen(), mbstowcs(), mbtowc(),
       setlocale(), toascii(), tolower(), __tolower(), toupper(), __toupper(),
       wcstombs(), wctomb()

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                           ctype.h(3)
