isalpha()

Test a character to see if it's alphabetic

Synopsis:

#include <ctype.h>

int isalpha( 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 isalpha() function tests if the argument c is an alphabetic character (a to z and A to Z). An alphabetic character is any character for which isupper() or islower() is true.

Returns:

Nonzero if c is an alphabetic character; otherwise, zero.

Examples:

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

int main( void )
{
    if( isalpha( getchar() ) ) {
      printf( "That's alphabetic\n" );
    }
    
    return EXIT_SUCCESS;
}

Classification:

ANSI, POSIX 1003.1

Safety:
Cancellation point	No
Interrupt handler	Yes
Signal handler	Yes
Thread	Yes