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 .