Hi,
> hi ,
> I couldn't even get the statement
> "it says such macros are used to have a
> block of statements without errors on subsitution."
The statement was not properly phrased. I am copying the example from
kernelnewbie FAQ to clarify what I tried to mean. And thanks a lot for
all the responses.
-Shourya
================================================
(from Per Persson) As both Miller and Collins point out, you want a
block statement so you can have several lines of code and declare
local variables. But then the natural thing would be to just use for
example:
#define exch(x,y) { int tmp; tmp=x; x=y; y=tmp; }
However that wouldn't work in some cases. The following code is meant
to be an if-statement with two branches:
if(x>y)
exch(x,y); // Branch 1
else
do_something(); // Branch 2
But it would be interpreted as an if-statement with only one branch:
if(x>y) { // Single-branch if-statement!!!
int tmp; // The one and only branch consists
tmp = x; // of the block.
x = y;
y = tmp;
}
; // empty statement
else // ERROR!!! "parse error before else"
do_something();
================================================
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