RE: iconv query

True, but in that case you're passing a pointer (address) and not the
variable. For instance on the call to fscanf() you need to pass an
array
name (address of first element) or the address operator (&) with the
correct
operand/variable. The arguments (pointers in this case) themselves are
passed by value. The variable addressed by the pointer can certainly be
changed, no argument there. My confusion is with the assertion that
structs
(or anything else for that matter) are not passed by value (by default)
when calling a function using C.

On Fri, Feb 5, 2010 at 9:51 AM, Dennis Lovelady
<iseries@xxxxxxxxxxxx>wrote:

I'm confused. With C, when calling a function, all argument
(parameter) passing is is by value. That's how C is defined. By
convention
many functions may pass by value a pointer to the struct, and with
arrays it
gets a little muddy as an array is really a pointer to the first
element
(though the pointer again is passed by value), but that's an
implementation
decision of the function provider, not C.

Not quite. When you pass a pointer to a variable (as you would, say,

with

fscanf), you find that your variable can (will) be changed. You're

not

comparing apples with apples.

Dennis Lovelady
http://www.linkedin.com/in/dennislovelady
--
"No matter what side of an argument you're on, you always find some

people

on your side that you wish were on the other side."
-- Jascha Heifetz



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Regards,
Bruce
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www.powercl.com
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Having gone back and re-read what Scott said, I now see and agree with your
point, Bruce. But I also agree with Scott: from a performance standpoint it
is usually better to pass a pointer to a structure than it is to pass the
structure itself in c, especially if the structure is large. When you pass
the pointer, you are passing by reference.

Consider, for example, the FILE structure, and how we use it.

For reference: http://archive.midrange.com/midrange-l/201002/msg00269.html
"the vast majority of structures I've seen used in C are passed by
reference."

Dennis Lovelady
http://www.linkedin.com/in/dennislovelady
--
"Those who make the worst use of their time are the first to complain of its
shortness."
-- Jean de La Bruyre