bionic (3) isalnum.3posix.gz

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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
       isalnum, isalnum_l — test for an alphanumeric character


SYNOPSIS
       #include <ctype.h>

       int isalnum(int c);
       int isalnum_l(int c, locale_t locale);


DESCRIPTION
       For isalnum(): 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  isalnum()  and  isalnum_l() functions shall test whether c is a character of class alpha or digit 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  isalnum_l()  is  the  special  locale object
       LC_GLOBAL_LOCALE or is not a valid locale object handle.


RETURN VALUE
       The isalnum() and isalnum_l() functions  shall  return  non-zero  if  c  is  an  alphanumeric  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
       isalpha(),  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>, <stdio.h>


       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 .