1ISALPHA(3P)                POSIX Programmer's Manual               ISALPHA(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       isalpha - test for an alphabetic character
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SYNOPSIS

15       #include <ctype.h>
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17       int isalpha(int c);
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DESCRIPTION

21       The isalpha() function shall test whether c is  a  character  of  class
22       alpha  in the program's current locale; see the Base Definitions volume
23       of IEEE Std 1003.1-2001, Chapter 7, Locale.
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25       The c argument is an int, the value  of  which  the  application  shall
26       ensure  is  representable  as an unsigned char or equal to the value of
27       the macro EOF. If the argument has any other  value,  the  behavior  is
28       undefined.
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RETURN VALUE

31       The  isalpha()  function  shall  return  non-zero if c is an alphabetic
32       character; otherwise, it shall return 0.
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ERRORS

35       No errors are defined.
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37       The following sections are informative.
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EXAMPLES

40       None.
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APPLICATION USAGE

43       To ensure applications  portability,  especially  across  natural  lan‐
44       guages,  only  this  function  and those listed in the SEE ALSO section
45       should be used for character classification.
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RATIONALE

48       None.
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FUTURE DIRECTIONS

51       None.
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SEE ALSO

54       isalnum(),  iscntrl(),  isdigit(),  isgraph(),  islower(),   isprint(),
55       ispunct(), isspace(), isupper(), isxdigit(), setlocale(), the Base Def‐
56       initions volume of IEEE Std 1003.1-2001, Chapter 7, Locale,  <ctype.h>,
57       <stdio.h>
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60       Portions  of  this text are reprinted and reproduced in electronic form
61       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
62       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
63       Specifications Issue 6, Copyright (C) 2001-2003  by  the  Institute  of
64       Electrical  and  Electronics  Engineers, Inc and The Open Group. In the
65       event of any discrepancy between this version and the original IEEE and
66       The  Open Group Standard, the original IEEE and The Open Group Standard
67       is the referee document. The original Standard can be  obtained  online
68       at http://www.opengroup.org/unix/online.html .
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72IEEE/The Open Group                  2003                          ISALPHA(3P)
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