isalnum(3p) — Linux manual page


ISALNUM(3P)             POSIX Programmer's Manual            ISALNUM(3P)

PROLOG         top

       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         top

       isalnum, isalnum_l — test for an alphanumeric character

SYNOPSIS         top

       #include <ctype.h>

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

DESCRIPTION         top

       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.1‐2017 defers to the ISO C

       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.1‐2017, 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         top

       The isalnum() and isalnum_l() functions shall return non-zero if
       c is an alphanumeric character; otherwise, they shall return 0.

ERRORS         top

       No errors are defined.

       The following sections are informative.

EXAMPLES         top



       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         top




SEE ALSO         top

       isalpha(3p), isblank(3p), iscntrl(3p), isdigit(3p), isgraph(3p),
       islower(3p), isprint(3p), ispunct(3p), isspace(3p), isupper(3p),
       isxdigit(3p), setlocale(3p), uselocale(3p)

       The Base Definitions volume of POSIX.1‐2017, Chapter 7, Locale,
       ctype.h(0p), stdio.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 by the Institute of Electrical and Electronics
       Engineers, Inc and The Open Group.  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 .

       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 .

IEEE/The Open Group               2017                       ISALNUM(3P)

Pages that refer to this page: ctype.h(0p)isalpha(3p)isblank(3p)iscntrl(3p)isdigit(3p)isgraph(3p)islower(3p)isprint(3p)ispunct(3p)isspace(3p)isupper(3p)isxdigit(3p)setlocale(3p)