Standard C Library Functions ctype(3C)
NAME
ctype, isalpha, isalnum, isascii, isblank, iscntrl, isdigit,islower, isprint, isspace, isupper, ispunct, isgraph, isxdi-
git - character handling
SYNOPSIS
#include
int isalpha(int c); int isalnum(int c); int isascii(int c); int isblank(int c); int iscntrl(int c); int isdigit(int c); int isgraph(int c); int islower(int c); int isprint(int c); int ispunct(int c);int isspace(int c);
int isupper(int c); int isxdigit(int c);DESCRIPTION
These macros classify character-coded integer values. Each
is a predicate returning non-zero for true, 0 for false. The
behavior of these macros, except isascii(), is affected by the current locale (see setlocale(3C)). To modify theSunOS 5.11 Last change: 28 Jan 2005 1
Standard C Library Functions ctype(3C)behavior, change the LC_TYPE category in setlocale(), that
is, setlocale(LC_CTYPE, newlocale). In the "C" locale, or in
a locale where character type information is not defined,characters are classified according to the rules of the US-
ASCII 7-bit coded character set.
The isascii() macro is defined on all integer values. The rest are defined only where the argument is an int, the value of which is representable as an unsigned char, or EOF, which is defined by theheader and represents end-of-file.
Functions exist for all the macros defined below. To get thefunction form, the macro name must be undefined (for exam-
ple, #undef isdigit).
For macros described with Default and Standard conformingversions, standard-conforming behavior is provided for
standard-conforming applications (see standards(5)) and for
applications that define __XPG4_CHAR_CLASS__ before includ-
ing. Default isalpha() Tests for any character for which isupper() or islower() is true. Standard conforming isalpha() Tests for any character for which isupper() or islower() is true, or any character that is one of the current locale-defined set of characters
for which none of iscntrl(), isdigit(),ispunct(), or isspace() is true. In "C" locale,
isalpha() returns true only for the characters for which isupper() or islower() is true. isalnum() Tests for any character for which isalpha() or isdigit() is true (letter or digit). isascii() Tests for any ASCII character, code between 0 and 0177 inclusive. isblank() Tests whether c is a character of class blank in the current locale. This macro/function is not available to applications conforming to standards prior to SUSv3. See standards(5)SunOS 5.11 Last change: 28 Jan 2005 2
Standard C Library Functions ctype(3C) iscntrl() Tests for any ``control character'' as defined by the character set.isdigit() Tests for any decimal-digit character.
Default isgraph() Tests for any character for which ispunct(), isupper(), islower(), and isdigit() is true. Standard conforming isgraph() Tests for any character for which isalnum() and ispunct() are true, or any character in thecurrent locale-defined "graph" class which is
neither a space ("") nor a character for which iscntrl() is true.islower() Tests for any character that is a lower-case
letter or is one of the current locale-defined
set of characters for which none of iscntrl(),isdigit(), ispunct(), isspace(), or isupper()
is true. In the "C" locale, islower() returnstrue only for the characters defined as lower-
case ASCII characters. Default isprint() Tests for any character for which ispunct(), isupper(), islower(), isdigit(), and the space character ("") is true. Standard conforming isprint() Tests for any character for which iscntrl() is false, and isalnum(), isgraph(), ispunct(), the space character (""), and the characters in thecurrent locale-defined "print" class are true.
ispunct() Tests for any printing character which is nei-
ther a space ("") nor a character for which isalnum() or iscntrl() is true.isspace() Tests for any space, tab, carriage-return, new-
line, vertical-tab or form-feed (standard
white-space characters) or for one of the
current locale-defined set of characters for
which isalnum() is false. In the "C" locale,SunOS 5.11 Last change: 28 Jan 2005 3
Standard C Library Functions ctype(3C)isspace() returns true only for the standard
white-space characters.
isupper() Tests for any character that is an upper-case
letter or is one of the current locale-defined
set of characters for which none of iscntrl(),isdigit(), ispunct(), isspace(), or islower()
is true. In the "C" locale, isupper() returnstrue only for the characters defined as upper-
case ASCII characters. Defaultisxdigit() Tests for any hexadecimal-digit character
([0-9], [A-F], or [a-f]).
Standard conformingisxdigit() Tests for any hexadecimal-digit character
([0-9], [A-F], or [a-f] or the current
locale-defined sets of characters representing
the hexadecimal digits 10 to 15 inclusive). In the "C" locale, only 0 1 2 3 4 5 6 7 8 9 A B C D E F a b c d e f are included.RETURN VALUES
If the argument to any of the character handling macros is not in the domain of the function, the result is undefined.Otherwise, the macro or function returns non-zero if the
classification is TRUE and 0 if the classification is FALSE.USAGE
These macros or functions can be used safely in mul-
tithreaded applications, as long as setlocale(3C) is not being called to change the locale.ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:SunOS 5.11 Last change: 28 Jan 2005 4
Standard C Library Functions ctype(3C)____________________________________________________________
| ATTRIBUTE TYPE ATTRIBUTE VALUE |
| CSI Enabled | | Interface Stability Committed || MT-Level MT-Safe with exceptions |
| Standard See standards(5). ||___________________________________________________________|
SEE ALSO
setlocale(3C), stdio(3C), ascii(5), environ(5), standards(5)SunOS 5.11 Last change: 28 Jan 2005 5