C Language: iscntrl function
(Test for Control Character)
In the C Programming Language, the iscntrl function tests whether c is a control character.
Syntax
The syntax for the iscntrl function in the C Language is:
int iscntrl(int c);
Parameters or Arguments
- c
- The value to test whether it is a control character.
Returns
The iscntrl function returns a nonzero value if c is a control character and returns zero if c is not a control character.
Required Header
In the C Language, the required header for the iscntrl function is:
#include <ctype.h>
Applies To
In the C Language, the iscntrl function can be used in the following versions:
- ANSI/ISO 9899-1990
iscntrl Example
/* Example using iscntrl by TechOnTheNet.com */
#include <stdio.h>
#include <ctype.h>
int main(int argc, const char * argv[])
{
/* Define a temporary variable */
unsigned char test;
/* Assign a test control character to the variable */
test = 0; /* This is NUL */
/* Test to see if this is a control character */
if (iscntrl(test) != 0) printf("NUL is a control character\n");
else printf("NUL is not a control character\n");
/* Assign a non-control character to the variable */
test = 'T';
/* Test to see if this is a control character */
if (iscntrl(test) != 0) printf("%c is a control character\n", test);
else printf("%c is not a control character\n", test);
return 0;
}
When compiled and run, this application will output:
NUL is a control character T is not a control character
Similar Functions
Other C functions that are similar to the iscntrl function:
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