SAS/C Library Reference, Vol. 1

iscsymf -- Test for Valid C Identifier Initial Symbol

SYNOPSIS

 #include <lctype.h>

 int iscsymf(int c);

DESCRIPTION

iscsymf tests an integer value to determine whether it is a character that can appear as the first character of a C identifier. For this implementation, the uppercase and lowercase alphabetic characters and the underscore are included.

RETURN VALUE

iscsymf returns 0 if the character is not a valid first character in a C identifier, or a nonzero value if it is. If the argument is EOF, 0 is returned.

CAUTION

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

EXAMPLE

  #include <lctype.h>
  #include <stdio.h>

  #define IDMAX 40

  main()
  {
     char id[IDMAX+1];
     int i;
     char *text;
     char input[IDMAX];

     puts("Enter any identifier (no more than 40 characters long).");
     text = gets(input);

        /* Copy a C identifier from text to id. */
     if (iscsymf(text[0])) {
        id[0] = text[0];

        for (i = 1; i < IDMAX && iscsym(text[i]); ++i)
           id[i] = text[i];

        id[i] = '0';

        printf("The identifier is copied as %sn", id);
     }
     else
        puts("The first character of identifier is not acceptable.);
  }

RELATED FUNCTIONS

iscsym