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ISALPHA(3)		   Linux Programmer's Manual		    ISALPHA(3)

NAME

isalnum, isalpha, isascii, isblank, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isspace, isupper, isxdigit - character classification routines

SYNOPSIS

#include <ctype.h> int isalnum(int c); int isalpha(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 functions check whether c, which must have the value of an unsigned char or EOF, falls into a certain character class according to the current locale. isalnum() checks for an alphanumeric character; it is equivalent to (isal- pha(c) || isdigit(c)). isalpha() checks for an alphabetic character; in the standard "C" locale, it is equivalent to (isupper(c) || islower(c)). In some locales, there may be additional characters for which isalpha() is true--letters which are neither upper case nor lower case. isascii() checks whether c is a 7-bit unsigned char value that fits into the ASCII character set. isblank() checks for a blank character; that is, a space or a tab. iscntrl() checks for a control character. isdigit() checks for a digit (0 through 9). isgraph() checks for any printable character except space. islower() checks for a lower-case character. isprint() checks for any printable character including space. ispunct() checks for any printable character which is not a space or an alphanumeric character. isspace() checks for white-space characters. In the "C" and "POSIX" locales, these are: space, form-feed ('\f'), newline ('\n'), carriage return ('\r'), horizontal tab ('\t'), and vertical tab ('\v'). isupper() checks for an uppercase letter. isxdigit() checks for a hexadecimal digits, i.e. one of 0 1 2 3 4 5 6 7 8 9 a b c d e f A B C D E F.

RETURN VALUE

The values returned are non-zero if the character c falls into the tested class, and a zero value if not.

CONFORMING TO

C99, 4.3BSD. isascii() is a BSD extension and is also an SVr4 exten- sion. isblank() conforms to POSIX.1-2001 and C99 7.4.1.3.

NOTE

The details of what characters belong into which class depend on the current locale. For example, isupper() will not recognize an A-umlaut (A) as an uppercase letter in the default C locale.

SEE ALSO

iswalnum(3), iswalpha(3), iswblank(3), iswcntrl(3), iswdigit(3), iswgraph(3) , iswlower(3), iswprint(3), iswpunct(3), iswspace(3), iswupper(3) , iswxdigit(3), setlocale(3), tolower(3), toupper(3), ascii(7), locale(7) GNU 1995-09-02 ISALPHA(3)

1994 Man-cgi 1.15, Panagiotis Christias <christia@theseas.ntua.gr>