Lint can't say it's an Error. Read K&R and you find out it's perfectly
right. How else could expresiions like this work in C:
a=b=c=0 ??
If c=0 returns tru because the assignment worked (like in Pascal e.g.)
then b would be 1 So you would have instead:
a=1
b=1
c=0
But in "reality you get:
a=0
b=0
c=0
And if you read K&R then you see that the code
if (i=fork()) { /* Do something */ } else { /* Do something */ } is
perfectly right C.
If you don't need the return-value anymore you can also write:
if (fork()) { /* Do something */ } else { /* Do something */ }
This is perfect standard C as well.
The difference between the two statements is that i got assigned the
return-value of fork an the result of this assignment is the right side
of the =-assignment so this means the return-value of fork. So you see
the can be every value you like.
If you don't believe it, I assume you begin learning C. There is a damn
good book written by K&R. (I hope you know K&R the developer of the
C-programming-language).
> Further, previous text states why. Any time I point out these things
> I get a bunch of fanatical "tool gurus" responding that I don't
> know what I'm talking about.
No the answers aren't fanatical. Perhaps you should learn the basics
before you build up such a mind which IS definatly wrong. You could even
learn from the answers you get instead of saying "These idiots don't
know what they are speaking about. I know everything so they can't be
right. I am God!!!"
Think about it.
> The 'C' language is just a tool. It is not a religion. It is also
> not a means unto itself. In the "real world", I don't give a damn
> about what you can get away with while using such a tool.
Yes, but you have to know the standards, what is allowed and what not.
You can't write Pascal-Code and hope the C-Compiler gets it right.
> I'll bet a dollar that there are few that have even seen Commercial
> Software that was reviewed by the FDA or DOD. If you want to pass
> the muster, take a lesson.
Well you can believe me that I have seen many commercial C-Compilers and
ALL work that way, because it's STANDARD-C-BEHAVIOUR.
> The ONLY reason why the 'C' Language is now allowed instead of ADA
> in Government end-user applications is because of persons like me
> who specified and signed up to some minimum standards. These standards
> say nothing about style, but make damn certain that the compiler(s)
> to be used generate the code specified. This means that some sloppy
> constructs are simply not allowed.
Read the standard from K&R (this is really the minimum ALL C-Compilers
know about).
> That said, the problem with:
>
> if(a=b)
>
> is that the value of a is not tested. 'a' got assigned the value of
> 'b', but only the assignment was tested, not the resulting value.
Right, but the assignment returns the RHS-value so the value of b.
> This, as I explained over and over again, is called a
> "boolean test of assignment error". It is a real error because,
> unless the machine crashed, it is always TRUE. This is what
> Lint is complaining about. One needs to test the result. You
> can do this by adding a sequence-point.
Clearly wrong. Read my mail.
Bye Martin
P.S.: I said nothing till now, because I thought you will learn the
right way. So I will say nothing more after this. If you can't write C
leave it.
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