TBuffer streaming from Char *

From: George Heintzelman (gah@bnl.gov)
Date: Mon Sep 27 1999 - 23:18:55 MEST 

Hi,

I'm using TBuffers so I can use Root streamers for writing to 
non-filesystem places (in my case an oracle database, but that doesn't 
really matter) and in the course of working with some char * variables 
came upon this:

inline TBuffer &TBuffer::operator>>(Char_t *c)
{
   ReadString(c, sizeof(c));
   return *this;
}

inline TBuffer &TBuffer::operator<<(const Char_t *c)
{
   WriteString(c);
   return *this;
}

where ReadString takes a maximum number of bytes parameter and 
WriteString writes up to the terminating 0 in the string passed.

With this code, using operator>> on a Char_t * variable will not read 
in the reverse of one that was written with an operator<<, since the 
sizeof(c) call will always resolve to 4 or maybe 8 on some machines.

I think the best way to deal with that is for the operator>> to be 
cavalier about it and just overwrite memory, since it has no way of 
knowing how big the buffer it should write into is, and since the user 
programmer is working with char *'s, it's his responsibility to make 
sure the memory allocation and stuff is correct. If it breaks, one just 
shrugs and says, "you should've used TString..."; but I think it's 
unfair for the user to be bitten by operator>>  not reading in, in 
exactly the same way, what operator<< wrote out.

George Heintzelman
gah@bnl.gov

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