CTYPE(3) Library Functions Manual CTYPE(3)NAME
isalpha, isupper, islower, isdigit, isalnum, isspace, ispunct, isprint, iscntrl, isascii - character classification
SYNOPSIS
#include <ctype.h>
isalpha(c)
. . .
DESCRIPTION
These macros classify ASCII-coded integer values by table lookup. Each is a predicate returning nonzero for true, zero for false. Isascii
is defined on all integer values; the rest are defined only where isascii is true and on the single non-ASCII value EOF (see stdio(3)).
isalpha c is a letter
isupper c is an upper case letter
islower c is a lower case letter
isdigit c is a digit
isalnum c is an alphanumeric character
isspace c is a space, tab, carriage return, newline, or formfeed
ispunct c is a punctuation character (neither control nor alphanumeric)
isprint c is a printing character, code 040(8) (space) through 0176 (tilde)
iscntrl c is a delete character (0177) or ordinary control character (less than 040).
isascii c is an ASCII character, code less than 0200
SEE ALSO ascii(7)CTYPE(3)
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CTYPE(3) Library Functions Manual CTYPE(3)NAME
isalpha, isupper, islower, isdigit, isxdigit, isalnum, isspace, ispunct, isprint, isgraph, iscntrl, isascii, toupper, tolower, toascii -
character classification macros
SYNOPSIS
#include <ctype.h>
isalpha(c)
. . .
DESCRIPTION
These macros classify ASCII-coded integer values by table lookup. Each is a predicate returning nonzero for true, zero for false. Isascii
and toascii are defined on all integer values; the rest are defined only where isascii is true and on the single non-ASCII value EOF (see
stdio(3S)).
isalpha c is a letter
isupper c is an upper case letter
islower c is a lower case letter
isdigit c is a digit
isxdigit c is a hex digit
isalnum c is an alphanumeric character
isspace c is a space, tab, carriage return, newline, vertical tab, or formfeed
ispunct c is a punctuation character (neither control nor alphanumeric)
isprint c is a printing character, code 040(8) (space) through 0176 (tilde)
isgraph c is a printing character, similar to isprint except false for space.
iscntrl c is a delete character(0177) or ordinary control character (less than 040).
isascii c is an ASCII character, code less than 0200
tolower c is converted to lower case. Return value is undefined if not isupper(c).
toupper c is converted to upper case. Return value is undefined if not islower(c).
toascii c is converted to be a valid ascii character.
SEE ALSO ascii(7)7th Edition May 12, 1986 CTYPE(3)
when i compile my program, i meet the following error:
...
undefined reference to `__ctype_b'
...
anybody knows which shared library should be linked during make?
thanks a lot! (6 Replies)
I am comparing two multibyte characters in two different platforms having different LC_CTYPE variables, they are returning different values.
One of the variable is sigma initialised to "\317\203"
and the other one is empty string i.e, ""
Below is the scenario of the two platforms:
In... (4 Replies)
Good Evening. I'm new to C. Can you please help me.
I'm creating an error checking function, user will input a string, this will check if the input is all alphabet or all letters only. If there is a digit or other special char, it will print Error then ask input from user again.
Here's my... (1 Reply)