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isalpha(3posix)


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.12008 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.12008, 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.12008,  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 .



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