isalpha

ISALPHA(3P)                POSIX Programmer's Manual               ISALPHA(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
       isalpha, isalpha_l — test for an alphabetic character

SYNOPSIS
       #include <ctype.h>

       int isalpha(int c);
       int isalpha_l(int c, locale_t locale);

DESCRIPTION
       For isalpha(): 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 isalpha() and isalpha_l() functions shall test whether c is a
       character of class alpha in the current locale, or in the locale
       represented by locale, respectively; see the Base Definitions volume of
       POSIX.1‐2008, Chapter 7, Locale.

       The c argument is an int, the value of which the application shall
       ensure is representable as an unsigned char or equal to the value of
       the macro EOF. If the argument has any other value, the behavior is
       undefined.

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

RETURN VALUE
       The isalpha() and isalpha_l() functions shall return non-zero if c is
       an alphabetic character; otherwise, they shall return 0.

ERRORS
       No errors are defined.

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       To ensure applications portability, especially across natural
       languages, only these functions and the functions in the reference
       pages listed in the SEE ALSO section should be used for character
       classification.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       isalnum(), isblank(), iscntrl(), isdigit(), isgraph(), islower(),
       isprint(), ispunct(), isspace(), isupper(), isxdigit(), setlocale(),
       uselocale()

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



IEEE/The Open Group                  2013                          ISALPHA(3P)