SAS/C Library Reference, Vol. 1

isspace -- White Space Test

SYNOPSIS

 #include <ctype.h>

 int isspace(int c);

DESCRIPTION

isspace tests an integer value c to determine whether it is white space; that is, a blank, tab, new line, carriage return, form feed, or vertical tab character. In the 5370 and POSIX locales, isspace returns true only for standard white-space characters.

RETURN VALUE

isspace returns 0 if the character is not white space, or a nonzero value if it is. If the argument is EOF, 0 is returned.

CAUTION

The effect of isspace on a noncharacter argument other than EOF is undefined. Do not assume that isspace returns either 0 or 1.

EXAMPLE

  #include <ctype.h>
  #include <stdio.h>
  #include <stdlib.h>

  main()
  {

     int c, n;
     puts("Enter a character when prompted.. even spaces are OK.");
     for (n = 1;; n++ )  {
        puts("Enter now (q to quit):  ");
        c = getchar();
        if (c == 'q') exit(0);
        printf("The character you entered %s a space charactern",
               isspace(c) ? "is" : "is not");
        if (c != 'n')
           getchar();                      /* Read the new line. */
     }
  }

RELATED FUNCTIONS

iscntrl, isgraph