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From: aduncan@rhea.trl.oz.au (Allan Duncan)
Newsgroups: comp.sys.amiga.tech
Subject: Re:  I/O of complex data structures in C
Message-ID: <2057@trlluna.trl.oz>
Date: 9 Aug 90 22:53:57 GMT
References: <dillon.5326@overload.Berkeley.CA.US>
Sender: root@trlluna.trl.oz
Lines: 31

From article <dillon.5326@overload.Berkeley.CA.US>, by dillon@overload.Berkeley.CA.US (Matthew Dillon):
>     fwrite(ptr, blockSize, numBlocks, fi);
 
>     const void *ptr;		pointer into memory, fwrite does not know or
> 				care what the pointer is actually pointing
> 				to!  const means the memory is not modified
> 				by fwrite() (obvious).
 
>     int blockSize;		fwrite writes blockSize * numBlocks bytes
>     int numBlocks;		of data from the memory location given by
> 				'ptr' to the file, no interpretation of the
> 				data is done.

Where did you find this?  It doesn't exist in K&R.  From V7 UNIX
Programmer's Manual :

fwrite( ptr, sizeof( *ptr ), nitems, stream )

fwrite appends at most nitems of data of the type *ptr beginning at ptr
to the named output stream.  It returns the number of items actually
written.

So you can see that the two are _not_ the same.  In detail, you either
write an item, or you don't - no half written items are permitted.
I looked at the source for the Manx call, and it uses two for loops to
call fputc(), not multiply block by items, then one loop.

Allan Duncan	ACSnet	a.duncan@trl.oz
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