| .\" (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de) |
| .\" |
| .\" Permission is granted to make and distribute verbatim copies of this |
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| .\" Permission is granted to copy and distribute modified versions of this |
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| .\" 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| .\" manual page may be incorrect or out-of-date.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 |
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| .\" which is licensed free of charge, as they might when working |
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| .\" Formatted or processed versions of this manual, if unaccompanied by |
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| .\" 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 |
| .BR isalnum () |
| checks for an alphanumeric character; it is equivalent to |
| .BI "(isalpha(" c ") || isdigit(" c "))" \fR. |
| .TP |
| .BR 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 |
| .BR isalpha () |
| is true\(emletters which are neither upper case nor lower |
| case. |
| .TP |
| .BR 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 |
| .BR isblank () |
| checks for a blank character; that is, a space or a tab. |
| .TP |
| .BR iscntrl () |
| checks for a control character. |
| .TP |
| .BR isdigit () |
| checks for a digit (0 through 9). |
| .TP |
| .BR isgraph () |
| checks for any printable character except space. |
| .TP |
| .BR islower () |
| checks for a lower-case character. |
| .TP |
| .BR isprint () |
| checks for any printable character including space. |
| .TP |
| .BR ispunct () |
| checks for any printable character which is not a space or an |
| alphanumeric character. |
| .TP |
| .BR 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 |
| .BR isupper () |
| checks for an uppercase letter. |
| .TP |
| .BR 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, |
| .BR 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) |