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Test a character to see if it's alphabetic
#include <ctype.h> int isalpha( int c );
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
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.
Nonzero if c is an alphabetic character; otherwise, zero.
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
int main( void )
{
    if( isalpha( getchar() ) ) {
      printf( "That's alphabetic\n" );
    }
    
    return EXIT_SUCCESS;
}
| Safety: | |
|---|---|
| Cancellation point | No | 
| Interrupt handler | Yes | 
| Signal handler | Yes | 
| Thread | Yes | 
isalnum(), iscntrl(), isdigit(), isgraph(), islower(), isprint(), ispunct(), isspace(), isupper(), iswalpha(), isxdigit(), tolower(), toupper()
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