This version of this document is no longer maintained. For the latest documentation, see http://www.qnx.com/developers/docs.

isspace()

Test a character to see if it's a whitespace character

Synopsis:

#include <ctype.h>

int isspace( int c );

Arguments:

c

The character you want to test.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The isspace() function tests for the following whitespace characters:

' '

space

'\f'

form feed

'\n'

newline or linefeed

'\r'

carriage return

'\t'

horizontal tab

'\v'

vertical tab

Returns:

Nonzero if c is a whitespace character; otherwise, zero.

Examples:

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

char the_chars[] = { 'A', 0x09, ' ', 0x7d };

#define SIZE sizeof( the_chars ) / sizeof( char )

int main( void )
{
    int i;

    for( i = 0; i < SIZE; i++ ) {
        if( isspace( the_chars[i] ) ) {
            printf( "Char %c is a space character\n",
                the_chars[i] );
        } else {
            printf( "Char %c is not a space character\n",
                the_chars[i] );
        }
    }
    
    return EXIT_SUCCESS;
}

This program produces the output:

Char A is not a space character
Char     is a space character
Char   is a space character
Char } is not a space character

Classification:

ANSI, POSIX 1003.1

See also:

isalnum(), isalpha(), iscntrl(), isdigit(), isgraph(), islower(), isprint(), ispunct(), isupper(), isxdigit(), tolower(), toupper()