Defined in header <cctype> | ||
---|---|---|
int iscntrl( int ch ); |
Checks if the given character is a control character as classified by the currently installed C locale. In the default, "C" locale, the control characters are the characters with the codes 0x00-0x1F
and 0x7F
.
The behavior is undefined if the value of ch
is not representable as unsigned char
and is not equal to EOF
.
Parameters
ch | - | character to classify |
Return value
Non-zero value if the character is a control character, zero otherwise.
Example
#include <iostream> #include <cctype> #include <clocale> int main() { unsigned char c = '\x94'; // the control code CCH in ISO-8859-1 std::cout << "iscntrl(\'\\x94\', default C locale) returned " << std::boolalpha << (bool)std::iscntrl(c) << '\n'; std::setlocale(LC_ALL, "en_GB.iso88591"); std::cout << "iscntrl(\'\\x94\', ISO-8859-1 locale) returned " << std::boolalpha << (bool)std::iscntrl(c) << '\n'; }
Output:
iscntrl('\x94', default C locale) returned false iscntrl('\x94', ISO-8859-1 locale) returned true
See also
checks if a character is classified as a control character by a locale (function template) | |
checks if a wide character is a control character (function) | |
C documentation for iscntrl |
ASCII values (hex) | characters |
| ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0 - 8 | 0x00-0x08 | control codes (NUL , etc.) | ≠0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
9 | 0x09 | tab (\t ) | ≠0 | 0 | ≠0 | ≠0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
10 - 13 | 0x0A-0x0D | whitespaces (\n ,\v ,\f ,\r ) | ≠0 | 0 | ≠0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
14 - 31 | 0x0E-0x1F | control codes | ≠0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
32 | 0x20 | space | 0 | ≠0 | ≠0 | ≠0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
33 - 47 | 0x21-0x2F | !"#$%&'()*+,-./ | 0 | ≠0 | 0 | 0 | ≠0 | ≠0 | 0 | 0 | 0 | 0 | 0 | 0 |
48 - 57 | 0x30-0x39 | 0123456789 | 0 | ≠0 | 0 | 0 | ≠0 | 0 | ≠0 | 0 | 0 | 0 | ≠0 | ≠0 |
58 - 64 | 0x3a-0x40 | :;<=>?@ | 0 | ≠0 | 0 | 0 | ≠0 | ≠0 | 0 | 0 | 0 | 0 | 0 | 0 |
65 - 70 | 0x41-0x46 | ABCDEF | 0 | ≠0 | 0 | 0 | ≠0 | 0 | ≠0 | ≠0 | ≠0 | 0 | 0 | ≠0 |
71 - 90 | 0x47-0x5A | GHIJKLMNOPQRSTUVWXYZ | 0 | ≠0 | 0 | 0 | ≠0 | 0 | ≠0 | ≠0 | ≠0 | 0 | 0 | 0 |
91 - 96 | 0x5B-0x60 | [\]^_` | 0 | ≠0 | 0 | 0 | ≠0 | ≠0 | 0 | 0 | 0 | 0 | 0 | 0 |
97 -102 | 0x61-0x66 | abcdef | 0 | ≠0 | 0 | 0 | ≠0 | 0 | ≠0 | ≠0 | 0 | ≠0 | 0 | ≠0 |
103-122 | 0x67-0x7A | ghijklmnopqrstuvwxyz | 0 | ≠0 | 0 | 0 | ≠0 | 0 | ≠0 | ≠0 | 0 | ≠0 | 0 | 0 |
123-126 | 0x7B-0x7E | {|}~ | 0 | ≠0 | 0 | 0 | ≠0 | ≠0 | 0 | 0 | 0 | 0 | 0 | 0 |
127 | 0x7F | backspace character (DEL ) | ≠0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
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