[thirdparty/man-pages.git] / man3 / isalpha.3

.\" (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de)
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\" 
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\" 
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\" License.
.\"
.\" Modified Sat Jul 24 19:10:00 1993 by Rik Faith (faith@cs.unc.edu)
.\" Modified Sun Aug 21 17:51:50 1994 by Rik Faith (faith@cs.unc.edu)
.\" Modified Sat Sep  2 21:52:01 1995 by Jim Van Zandt <jrv@vanzandt.mv.com>
.\" Modified Mon May 27 22:55:26 1996 by Martin Schulze (joey@linux.de)
.\"
.TH ISALPHA 3  1995-09-02 "GNU" "Linux Programmer's Manual"
.SH NAME
isalnum, isalpha, isascii, isblank, iscntrl, isdigit, isgraph, islower, 
isprint, ispunct, isspace, isupper, isxdigit \- character 
classification routines
.SH SYNOPSIS
.nf
.B #include <ctype.h>
.sp
.BI "int isalnum(int " "c" );
.nl
.BI "int isalpha(int " "c" );
.nl
.BI "int isascii(int " "c" );
.nl
.BI "int isblank(int " "c" );
.nl
.BI "int iscntrl(int " "c" );
.nl
.BI "int isdigit(int " "c" );
.nl
.BI "int isgraph(int " "c" );
.nl
.BI "int islower(int " "c" );
.nl
.BI "int isprint(int " "c" );
.nl
.BI "int ispunct(int " "c" );
.nl
.BI "int isspace(int " "c" );
.nl
.BI "int isupper(int " "c" );
.nl
.BI "int isxdigit(int " "c" );
.fi
.SH DESCRIPTION
These functions check whether
.IR c ,
which must have the value of an
.B unsigned char
or
.BR EOF ,
falls into a certain character class according to the current locale.
.TP 
.B "isalnum()"
checks for an alphanumeric character; it is equivalent to
.BI "(isalpha(" c ") || isdigit(" c "))" \fR.
.TP
.B "isalpha()"
checks for an alphabetic character; in the standard \fB"C"\fP 
locale, it is equivalent to
.BI "(isupper(" c ") || islower(" c "))" \fR.
In some locales, there may be additional characters for which
.B  isalpha()
is true\(emletters which are neither upper case nor lower
case.  
.TP
.B "isascii()"
checks whether \fIc\fP is a 7-bit
.I unsigned char
value that fits into
the ASCII character set.  This function is a BSD extension
and is also an SVID extension.
.TP
.B "isblank()"
checks for a blank character; that is, a space or a tab.
.TP
.B "iscntrl()"
checks for a control character.
.TP
.B "isdigit()"
checks for a digit (0 through 9).
.TP
.B "isgraph()"
checks for any printable character except space.
.TP
.B "islower()"
checks for a lower-case character.
.TP
.B "isprint()"
checks for any printable character including space.
.TP
.B "ispunct()"
checks for any printable character which is not a space or an
alphanumeric character.
.TP
.B "isspace()"
checks for white-space characters.  In the
.B """C"""
and
.B """POSIX"""
locales, these are: space, form-feed
.RB ( '\ef' ),
newline
.RB ( '\en' ),
carriage return
.RB ( '\er' ),
horizontal tab
.RB ( '\et' ),
and vertical tab
.RB ( '\ev' ).
.TP
.B "isupper()"
checks for an uppercase letter.
.TP
.B "isxdigit()"
checks for a hexadecimal digits, i.e. one of
.nl
.BR "0 1 2 3 4 5 6 7 8 9 a b c d e f A B C D E F" .
.SH "RETURN VALUE"
The values returned are non-zero if the character
.I c
falls into the tested class, and a zero value 
if not.
.SH "CONFORMING TO"
ANSI-C, 4.3BSD.
\fBisascii()\fP is a BSD extension
and is also an SVID extension.
\fBisblank()\fP conforms to ISO C99 7.4.1.3.
.SH NOTE
The details of what characters belong into which class depend on the current
locale.  For example,
.B isupper()
will not recognize an A-umlaut (\(:A) as an uppercase letter in the default
.B "C"
locale.
.SH "SEE ALSO"
.BR setlocale (3),
.BR tolower (3),
.BR toupper (3),
.BR ascii (7),
.BR locale (7)
Commit	Line	Data
fea681da MK	1	.\" (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de)
	2	.\"
	3	.\" Permission is granted to make and distribute verbatim copies of this
	4	.\" manual provided the copyright notice and this permission notice are
	5	.\" preserved on all copies.
	6	.\"
	7	.\" Permission is granted to copy and distribute modified versions of this
	8	.\" manual under the conditions for verbatim copying, provided that the
	9	.\" entire resulting derived work is distributed under the terms of a
	10	.\" permission notice identical to this one.
	11	.\"
	12	.\" Since the Linux kernel and libraries are constantly changing, this
	13	.\" manual page may be incorrect or out-of-date. The author(s) assume no
	14	.\" responsibility for errors or omissions, or for damages resulting from
	15	.\" the use of the information contained herein. The author(s) may not
	16	.\" have taken the same level of care in the production of this manual,
	17	.\" which is licensed free of charge, as they might when working
	18	.\" professionally.
	19	.\"
	20	.\" Formatted or processed versions of this manual, if unaccompanied by
	21	.\" the source, must acknowledge the copyright and authors of this work.
	22	.\" License.
	23	.\"
	24	.\" Modified Sat Jul 24 19:10:00 1993 by Rik Faith (faith@cs.unc.edu)
	25	.\" Modified Sun Aug 21 17:51:50 1994 by Rik Faith (faith@cs.unc.edu)
	26	.\" Modified Sat Sep 2 21:52:01 1995 by Jim Van Zandt <jrv@vanzandt.mv.com>
	27	.\" Modified Mon May 27 22:55:26 1996 by Martin Schulze (joey@linux.de)
	28	.\"
	29	.TH ISALPHA 3 1995-09-02 "GNU" "Linux Programmer's Manual"
	30	.SH NAME
	31	isalnum, isalpha, isascii, isblank, iscntrl, isdigit, isgraph, islower,
	32	isprint, ispunct, isspace, isupper, isxdigit \- character
	33	classification routines
	34	.SH SYNOPSIS
	35	.nf
	36	.B #include <ctype.h>
	37	.sp
	38	.BI "int isalnum(int " "c" );
	39	.nl
	40	.BI "int isalpha(int " "c" );
	41	.nl
	42	.BI "int isascii(int " "c" );
	43	.nl
	44	.BI "int isblank(int " "c" );
	45	.nl
	46	.BI "int iscntrl(int " "c" );
	47	.nl
	48	.BI "int isdigit(int " "c" );
	49	.nl
	50	.BI "int isgraph(int " "c" );
	51	.nl
	52	.BI "int islower(int " "c" );
	53	.nl
	54	.BI "int isprint(int " "c" );
	55	.nl
	56	.BI "int ispunct(int " "c" );
	57	.nl
	58	.BI "int isspace(int " "c" );
	59	.nl
	60	.BI "int isupper(int " "c" );
	61	.nl
	62	.BI "int isxdigit(int " "c" );
	63	.fi
	64	.SH DESCRIPTION
65	These functions check whether
66	.IR c ,
67	which must have the value of an
68	.B unsigned char
69	or
70	.BR EOF ,
71	falls into a certain character class according to the current locale.
72	.TP
73	.B "isalnum()"
74	checks for an alphanumeric character; it is equivalent to
75	.BI "(isalpha(" c ") \|\| isdigit(" c "))" \fR.
76	.TP
77	.B "isalpha()"
78	checks for an alphabetic character; in the standard \fB"C"\fP
79	locale, it is equivalent to
80	.BI "(isupper(" c ") \|\| islower(" c "))" \fR.
81	In some locales, there may be additional characters for which
82	.B isalpha()
2bc2f479	83	is true\(emletters which are neither upper case nor lower
fea681da MK	84	case.
	85	.TP
	86	.B "isascii()"
	87	checks whether \fIc\fP is a 7-bit
	88	.I unsigned char
	89	value that fits into
	90	the ASCII character set. This function is a BSD extension
	91	and is also an SVID extension.
	92	.TP
	93	.B "isblank()"
	94	checks for a blank character; that is, a space or a tab.
	95	.TP
	96	.B "iscntrl()"
	97	checks for a control character.
	98	.TP
	99	.B "isdigit()"
	100	checks for a digit (0 through 9).
	101	.TP
	102	.B "isgraph()"
	103	checks for any printable character except space.
	104	.TP
	105	.B "islower()"
	106	checks for a lower-case character.
	107	.TP
	108	.B "isprint()"
	109	checks for any printable character including space.
	110	.TP
	111	.B "ispunct()"
	112	checks for any printable character which is not a space or an
	113	alphanumeric character.
	114	.TP
	115	.B "isspace()"
	116	checks for white-space characters. In the
	117	.B """C"""
	118	and
	119	.B """POSIX"""
	120	locales, these are: space, form-feed
	121	.RB ( '\ef' ),
	122	newline
	123	.RB ( '\en' ),
	124	carriage return
	125	.RB ( '\er' ),
	126	horizontal tab
	127	.RB ( '\et' ),
	128	and vertical tab
	129	.RB ( '\ev' ).
	130	.TP
	131	.B "isupper()"
	132	checks for an uppercase letter.
	133	.TP
	134	.B "isxdigit()"
	135	checks for a hexadecimal digits, i.e. one of
	136	.nl
	137	.BR "0 1 2 3 4 5 6 7 8 9 a b c d e f A B C D E F" .
	138	.SH "RETURN VALUE"
f59a3f19	139	The values returned are non-zero if the character
fea681da MK	140	.I c
	141	falls into the tested class, and a zero value
	142	if not.
	143	.SH "CONFORMING TO"
b14d4aa5	144	ANSI-C, 4.3BSD.
fea681da MK	145	\fBisascii()\fP is a BSD extension
	146	and is also an SVID extension.
	147	\fBisblank()\fP conforms to ISO C99 7.4.1.3.
	148	.SH NOTE
	149	The details of what characters belong into which class depend on the current
	150	locale. For example,
	151	.B isupper()
c65433e6	152	will not recognize an A-umlaut (\(:A) as an uppercase letter in the default
fea681da MK	153	.B "C"
	154	locale.
	155	.SH "SEE ALSO"
	156	.BR setlocale (3),
	157	.BR tolower (3),
	158	.BR toupper (3),
	159	.BR ascii (7),
	160	.BR locale (7)