Updated: April 19, 2023 |
Test a character to see if it's a control character
#include <ctype.h> int iscntrl( int c );
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
The iscntrl() function tests for any control character. An ASCII control character is any character whose value is between 0 and 31.
Nonzero if c is a control character; otherwise, zero.
#include <stdio.h> #include <stdlib.h> #include <ctype.h> char the_chars[] = { 'A', 0x09, 'Z' }; #define SIZE sizeof( the_chars ) / sizeof( char ) int main( void ) { int i; for( i = 0; i < SIZE; i++ ) { if( iscntrl( (unsigned)the_chars[i] ) ) { printf( "Char %c is a Control character\n", the_chars[i] ); } else { printf( "Char %c is not a Control character\n", the_chars[i] ); } } return EXIT_SUCCESS; }
produces the output:
Char A is not a Control character Char is a Control character Char Z is not a Control character
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | Yes |
Signal handler | Yes |
Thread | Yes |