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Technical Reference: Base Operating System and Extensions, Volume 1
Classifies characters.
Standard Character Library
(libc.a)
#include <ctype.h>
int isalpha ( Character)
int Character;
int isupper (Character)
int Character;
int islower (Character)
int Character;
int isdigit (Character)
int Character;
int isxdigit (Character)
int Character;
int isalnum (Character)
int Character;
int isspace (Character)
int Character;
int ispunct (Character)
int Character;
int isprint (Character)
int Character;
int isgraph (Character)
int Character;
int iscntrl (Character)
int Character;
int isascii (Character)
int Character;
The ctype subroutines
classify character-coded integer values specified in a table. Each of
these subroutines returns a nonzero value for True and 0 for False.
Note: The ctype subroutines should only be used
on character data that can be represented by a single byte value ( 0 through
255 ). Attempting to use the ctype subroutines on multi-byte
locale data may give inconsistent results. Wide character
classification routines (such as iswprint, iswlower,
etc.) should be used with dealing with multi-byte character
data.
The following subroutines return
nonzero (True) based upon the character class definitions for the current
locale.
isalnum
| Returns nonzero for any character for which the isalpha or
isdigit subroutine would return nonzero. The
isalnum subroutine tests whether the character is of the
alpha or digit class.
|
isalpha
| Returns nonzero for any character for which the isupper or
islower subroutines would return nonzero. The
isalpha subroutine also returns nonzero for any character defined
as an alphabetic character in the current locale, or for a character for which
none of the iscntrl, isdigit,
ispunct, or isspace subroutines would return
nonzero. The isalpha subroutine tests whether the character
is of the alpha class.
|
isupper
| Returns nonzero for any uppercase letter [A through Z]. The
isupper subroutine also returns nonzero for any character defined
to be uppercase in the current locale. The isupper
subroutine tests whether the character is of the upper
class.
|
islower
| Returns nonzero for any lowercase letter [a through z]. The
islower subroutine also returns nonzero for any character defined
to be lowercase in the current locale. The islower
subroutine tests whether the character is of the lower
class.
|
isspace
| Returns nonzero for any white-space character (space, form feed, new
line, carriage return, horizontal tab or vertical tab). The
isspace subroutine tests whether the character is of the
space class.
|
ispunct
| Returns nonzero for any character for which the isprint
subroutine returns nonzero, except the space character and any character for
which the isalnum subroutine would return nonzero. The
ispunct subroutine also returns nonzero for any locale-defined
character specified as a punctuation character. The ispunct
subroutine tests whether the character is of the punct
class.
|
isprint
| Returns nonzero for any printing character. Returns nonzero for
any locale-defined character that is designated a printing character.
This routine tests whether the character is of the print
class.
|
isgraph
| Returns nonzero for any character for which the isprint
character returns nonzero, except the space character. The
isgraph subroutine tests whether the character is of the
graph class.
|
iscntrl
| Returns nonzero for any character for which the isprint
subroutine returns a value of False (0) and any character that is designated a
control character in the current locale. For the C locale, control
characters are the ASCII delete character (0177 or 0x7F), or an ordinary
control character (less than 040 or 0x20). The iscntrl
subroutine tests whether the character is of the cntrl
class.
|
The following subroutines return
nonzero for the same characters, regardless of the locale:
isdigit
| Character is a digit in the range [0 through 9].
|
isxdigit
| Character is a hexadecimal digit in the range [0 through 9],
[A through F], or [a through f].
|
isascii
| Character is an ASCII character whose value is in the range 0
through 0177 (0 through 0x7F), inclusive.
|
Character
| Indicates the character to be tested (integer value).
|
The ctype subroutines
return nonzero (True) if the character specified by the Character
parameter is a member of the selected character class; otherwise, a 0
(False) is returned.
These subroutines are part of Base
Operating System (BOS) Runtime.
The setlocale subroutine.
List of Character
Manipulation Services and Subroutines Overview in
AIX 5L Version 5.1 General Programming Concepts: Writing and
Debugging Programs.
National Language Support Overview for Programming in
AIX 5L Version 5.1 General Programming Concepts: Writing and
Debugging Programs.
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