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ctype(3) [freebsd man page]

CTYPE(3)						   BSD Library Functions Manual 						  CTYPE(3)

NAME
digittoint, isalnum, isalpha, isascii, isblank, iscntrl, isdigit, isgraph, ishexnumber, isideogram, islower, isnumber, isphonogram, isprint, ispunct, isrune, isspace, isspecial, isupper, isxdigit, toascii, tolower, toupper -- character classification functions LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <ctype.h> int digittoint(int c); int isalnum(int c); int isalpha(int c); int isascii(int c); int iscntrl(int c); int isdigit(int c); int isgraph(int c); int ishexnumber(int c); int isideogram(int c); int islower(int c); int isnumber(int c); int isphonogram(int c); int isspecial(int c); int isprint(int c); int ispunct(int c); int isrune(int c); int isspace(int c); int isupper(int c); int isxdigit(int c); int toascii(int c); int tolower(int c); int toupper(int c); DESCRIPTION
The above functions perform character tests and conversions on the integer c. They are available as macros, defined in the include file <ctype.h>, or as true functions in the C library. See the specific manual pages for more information. SEE ALSO
digittoint(3), isalnum(3), isalpha(3), isascii(3), isblank(3), iscntrl(3), isdigit(3), isgraph(3), isideogram(3), islower(3), isphonogram(3), isprint(3), ispunct(3), isrune(3), isspace(3), isspecial(3), isupper(3), isxdigit(3), toascii(3), tolower(3), toupper(3), wctype(3), ascii(7) STANDARDS
These functions, except for digittoint(), isascii(), ishexnumber(), isideogram(), isnumber(), isphonogram(), isrune(), isspecial() and toascii(), conform to ISO/IEC 9899:1990 (``ISO C90''). BSD
March 30, 2004 BSD

Check Out this Related Man Page

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

NAME
isalnum, isalpha, isascii, isblank, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isspace, isupper, isxdigit - character classifi- cation 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 (isalpha(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. This function is a BSD extension and is also an SVID extension. isblank() checks for a blank character; that is, a space or a tab. This function is a GNU extension. 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 (' '), carriage return (' '), horizontal tab (' '), 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 nonzero if the character c falls into the tested class, and a zero value if not. CONFORMING TO
ANSI - C, BSD 4.3. isascii() is a BSD extension and is also an SVID extension. isblank() is a GNU extension. NOTE
The details of what characters belong into which class depend on the current locale. For example, isupper() will not recognize an A - umlaut as an uppercase letter in the default C locale. SEE ALSO
tolower(3), toupper(3), setlocale(3), ascii(7), locale(7) GNU
1995-09-02 ISALPHA(3)

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