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Portions of this text are reprinted and reproduced in electronic form in the Sun OS Reference Manual, from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between these versions 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 http://www.opengroup.org/unix/online.html. This notice shall appear on any product containing this material. .TH ctype 3C "28 Jan 2005" "SunOS 5.11" "Standard C Library Functions" .SH NAME ctype, isalpha, isalnum, isascii, isblank, iscntrl, isdigit, islower, isprint, isspace, isupper, ispunct, isgraph, isxdigit \- character handling .SH SYNOPSIS .LP .nf #include \fBint\fR \fBisalpha\fR(\fBint\fR \fIc\fR); .fi .LP .nf \fBint\fR \fBisalnum\fR(\fBint\fR \fIc\fR); .fi .LP .nf \fBint\fR \fBisascii\fR(\fBint\fR \fIc\fR); .fi .LP .nf \fBint\fR \fBisblank\fR(\fBint\fR \fIc\fR); .fi .LP .nf \fBint\fR \fBiscntrl\fR(\fBint\fR \fIc\fR); .fi .LP .nf \fBint\fR \fBisdigit\fR(\fBint\fR \fIc\fR); .fi .LP .nf \fBint\fR \fBisgraph\fR(\fBint\fR \fIc\fR); .fi .LP .nf \fBint\fR \fBislower\fR(\fBint\fR \fIc\fR); .fi .LP .nf \fBint\fR \fBisprint\fR(\fBint\fR \fIc\fR); .fi .LP .nf \fBint\fR \fBispunct\fR(\fBint\fR \fIc\fR); .fi .LP .nf \fBint\fR \fBisspace\fR(\fBint\fR \fIc\fR); .fi .LP .nf \fBint\fR \fBisupper\fR(\fBint\fR \fIc\fR); .fi .LP .nf \fBint\fR \fBisxdigit\fR(\fBint\fR \fIc\fR); .fi .SH DESCRIPTION .sp .LP These macros classify character-coded integer values. Each is a predicate returning non-zero for true, \fB0\fR for false. The behavior of these macros, except \fBisascii()\fR, is affected by the current locale (see \fBsetlocale\fR(3C)). To modify the behavior, change the \fBLC_TYPE\fR category in \fBsetlocale()\fR, that is, \fBsetlocale(\fR\fBLC_CTYPE\fR, \fInewlocale\fR). In the "C" locale, or in a locale where character type information is not defined, characters are classified according to the rules of the \fBUS-ASCII\fR 7-bit coded character set. .sp .LP The \fBisascii()\fR macro is defined on all integer values. The rest are defined only where the argument is an \fBint\fR, the value of which is representable as an \fBunsigned char\fR, or \fBEOF\fR, which is defined by the <\fBstdio.h\fR> header and represents end-of-file. .sp .LP Functions exist for all the macros defined below. To get the function form, the macro name must be undefined (for example, \fB#undef isdigit\fR). .sp .LP For macros described with \fBDefault\fR and \fBStandard conforming\fR versions, standard-conforming behavior is provided for standard-conforming applications (see \fBstandards\fR(5)) and for applications that define \fB__XPG4_CHAR_CLASS__\fR before including <\fBctype.h\fR>. .SS "Default" .sp .ne 2 .mk .na \fB\fBisalpha()\fR\fR .ad .RS 13n .rt Tests for any character for which \fBisupper()\fR or \fBislower()\fR is true. .RE .SS "Standard conforming" .sp .ne 2 .mk .na \fB\fBisalpha()\fR\fR .ad .RS 13n .rt Tests for any character for which \fBisupper()\fR or \fBislower()\fR is true, or any character that is one of the current locale-defined set of characters for which none of \fBiscntrl()\fR, \fBisdigit()\fR, \fBispunct()\fR, or \fBisspace()\fR is true. In "C" locale, \fBisalpha()\fR returns true only for the characters for which \fBisupper()\fR or \fBislower()\fR is true. .RE .sp .ne 2 .mk .na \fB\fBisalnum()\fR\fR .ad .RS 13n .rt Tests for any character for which \fBisalpha()\fR or \fBisdigit()\fR is true (letter or digit). .RE .sp .ne 2 .mk .na \fB\fBisascii()\fR\fR .ad .RS 13n .rt Tests for any ASCII character, code between \fB0\fR and \fB0177\fR inclusive. .RE .sp .ne 2 .mk .na \fB\fBisblank()\fR\fR .ad .RS 13n .rt Tests whether \fIc\fR 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 \fBstandards\fR(5) .RE .sp .ne 2 .mk .na \fB\fBiscntrl()\fR\fR .ad .RS 13n .rt Tests for any ``control character'' as defined by the character set. .RE .sp .ne 2 .mk .na \fB\fBisdigit()\fR\fR .ad .RS 13n .rt Tests for any decimal-digit character. .RE .SS "Default" .sp .ne 2 .mk .na \fB\fBisgraph()\fR\fR .ad .RS 13n .rt Tests for any character for which \fBispunct()\fR, \fBisupper()\fR, \fBislower()\fR, and \fBisdigit()\fR is true. .RE .SS "Standard conforming" .sp .ne 2 .mk .na \fB\fBisgraph()\fR\fR .ad .RS 13n .rt Tests for any character for which \fBisalnum()\fR and \fBispunct()\fR are true, or any character in the current locale-defined "graph" class which is neither a space ("\|") nor a character for which \fBiscntrl()\fR is true. .RE .sp .ne 2 .mk .na \fB\fBislower()\fR\fR .ad .RS 13n .rt 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 \fBiscntrl()\fR, \fBisdigit()\fR, \fBispunct()\fR, \fBisspace()\fR, or \fBisupper()\fR is true. In the "C" locale, \fBislower()\fR returns true only for the characters defined as lower-case \fBASCII\fR characters. .RE .SS "Default" .sp .ne 2 .mk .na \fB\fBisprint()\fR\fR .ad .RS 13n .rt Tests for any character for which \fBispunct()\fR, \fBisupper()\fR, \fBislower()\fR, \fBisdigit()\fR, and the space character ("\|") is true. .RE .SS "Standard conforming" .sp .ne 2 .mk .na \fB\fBisprint()\fR\fR .ad .RS 13n .rt Tests for any character for which \fBiscntrl()\fR is false, and \fBisalnum()\fR, \fBisgraph()\fR, \fBispunct()\fR, the space character ("\|"), and the characters in the current locale-defined "print" class are true. .RE .sp .ne 2 .mk .na \fB\fBispunct()\fR\fR .ad .RS 13n .rt Tests for any printing character which is neither a space ("\|") nor a character for which \fBisalnum()\fR or \fBiscntrl()\fR is true. .RE .sp .ne 2 .mk .na \fB\fBisspace()\fR\fR .ad .RS 13n .rt Tests for any space, tab, carriage-return, newline, vertical-tab or form-feed (standard white-space characters) or for one of the current locale-defined set of characters for which \fBisalnum()\fR is false. In the "C" locale, \fBisspace()\fR returns true only for the standard white-space characters. .RE .sp .ne 2 .mk .na \fB\fBisupper()\fR\fR .ad .RS 13n .rt 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 \fBiscntrl()\fR, \fBisdigit()\fR, \fBispunct()\fR, \fBisspace()\fR, or \fBislower()\fR is true. In the "C" locale, \fBisupper()\fR returns true only for the characters defined as upper-case \fBASCII\fR characters. .RE .SS "Default" .sp .ne 2 .mk .na \fB\fBisxdigit()\fR\fR .ad .RS 14n .rt Tests for any hexadecimal-digit character (\fB[0\(mi9]\fR, \fB[A\(miF]\fR, or \fB[a\(mif]\fR). .RE .SS "Standard conforming" .sp .ne 2 .mk .na \fB\fBisxdigit()\fR\fR .ad .RS 14n .rt Tests for any hexadecimal-digit character (\fB[0\(mi9]\fR, \fB[A\(miF]\fR, or \fB[a\(mif]\fR or the current locale-defined sets of characters representing the hexadecimal digits \fB10\fR to \fB15\fR inclusive). In the "C" locale, only .sp .in +2 .nf 0 1 2 3 4 5 6 7 8 9 A B C D E F a b c d e f .fi .in -2 are included. .RE .SH RETURN VALUES .sp .LP 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 \fBTRUE\fR and \fB0\fR if the classification is \fBFALSE\fR. .SH USAGE .sp .LP These macros or functions can be used safely in multithreaded applications, as long as \fBsetlocale\fR(3C) is not being called to change the locale. .SH ATTRIBUTES .sp .LP See \fBattributes\fR(5) for descriptions of the following attributes: .sp .sp .TS tab() box; lw(2.75i) lw(2.75i) lw(2.75i) lw(2.75i) . ATTRIBUTE TYPEATTRIBUTE VALUE CSIEnabled Interface StabilityCommitted MT-LevelMT-Safe with exceptions StandardSee \fBstandards\fR(5). .TE .SH SEE ALSO .sp .LP \fBsetlocale\fR(3C), \fBstdio\fR(3C), \fBascii\fR(5), \fBenviron\fR(5), \fBstandards\fR(5)