index(3)           UNIX System V(BSD Compatibility Package)            index(3)


NAME
      index, rindex - string operations

SYNOPSIS
      #include <string.h>

      char *index(s, c)
      char *s, c;

      char *rindex(s, c)
      char *s, c;

DESCRIPTION
      These functions operate on NULL-terminated strings.  They do not check
      for overflow of any receiving string.

      index and rindex returns a pointer to the first (last) occurrence of
      character c in string s, or a NULL pointer if c does not occur in the
      string.  The NULL character terminating a string is considered to be part
      of the string.

SEE ALSO
      bstring(3), strings(3)

      malloc(3C) in the Programmer's Reference Manual

NOTES
      For user convenience, these functions are declared in the optional
      <strings.h> header file.

      On the Sun processor, as well as on many other machines, you can not use
      a NULL pointer to indicate a NULL string.  A NULL pointer is an error and
      results in an abort of the program.  If you wish to indicate a NULL
      string, you must have a pointer that points to an explicit NULL string.
      On some implementations of the C language on some machines, a NULL
      pointer, if dereferenced, would yield a NULL string; this highly non-
      portable trick was used in some programs.  Programmers using a NULL
      pointer to represent an empty string should be aware of this portability
      issue; even on machines where dereferencing a NULL pointer does not cause
      an abort of the program, it does not necessarily yield a NULL string.

      Character movement is performed differently in different implementations.
      Thus overlapping moves may yield surprises.











10/89                                                                    Page 1