Header File 

ctype.h, wctype.h 

Category 

Classification Routines 

Prototype 

int isascii(int c); 

int iswascii(wint_t c); 

Description 

Character classification macro. 

These functions depend on the LC_CTYPE  

isascii is a macro that classifies ASCII-coded integer values by table lookup. It is a predicate returning nonzero for true and 0 for false. 

isascii is defined on all integer values. 

Return Value 

isascii returns nonzero if c is in the range 0 to 127 (0x00-0x7F). 

iswascii returns nonzero if c is is a wide-character representation of an ASCII character.  

Each of these routines returns 0 if c does not satisfy the test condition. 

Example  

#include <stdio.h>
#include <ctype.h>
#include <stdio.h>
int main(void)
{
  char c = 'C';
  if (isascii(c))
    printf("%c is ascii\n",c);
  else 
    printf("%c is not ascii\n",c);
  return 0;
}

Portability