Description
string 
iconv_substr ( string str, int offset [, int length [, string charset]] )
     Returns the portion of str specified by
     the start and length
     parameters.
    
     If start is non-negative,
     iconv_substr() cuts the portion out of
     str beginning at start'th
     character, counting from zero.
    
     If start is negative,
     iconv_substr() cuts out the portion beginning
     at the position, start characters
     away from the end of str.
    
     If length is given and is positive, the return
     value will contain at most length characters
     of the portion that begins at start
     (depending on the length of string).
     If str is shorter than start
     characters long, FALSE will be returned.
    
     If negative length is passed,
     iconv_substr() cuts the portion out of
     str from the start'th
     character up to the character that is
     length characters away from the end of the string.
     In case start is also negative, the start position
     is calculated beforehand according to the rule explained above.
    
     Note that offset and length
     parameters are always deemed to represent offsets that are 
     calculated on the basis of the character set determined by 
     charset, whilst the counterpart
     substr() always takes these for byte offsets.
     If charset is not given, the character set
     is determined by the iconv.internal_encoding
     ini setting. 
    
     See also substr(), mb_substr()
     and mb_strcut().