Thread: strange compiler

Originally Posted by Salem

VLA's are essentially useless candy IMO.

The biggest problem is what happens if your VLA no longer fits on the stack (assuming that is where VLAs get created on a given machine). Even the best scenario results in the program being killed by the OS. On an embedded system, it probably just trashes someone else's memory. Nor is there a way of finding out in advance whether it will succeed or not, just close your eyes, pray and take a jump.

Of course, a lot of naive programmers are going to take unchecked user input, and create their VLA directly from that. Most of them won't even bother to check for negative numbers, nevermind huge positive numbers.

At least with malloc, there is a clearly defined way of being told there is no more room, and from there you can take appropriate action.

Yes all true, but it has a place. If you need scratch memory allocated dynamically it can be quite convenient. For example if I'm doing a bunch of matrix operations, or even a bunch of rotations using quaternions for graphics applications, I'd like to be able to allocate some temp memory of small but possibly unknown size; use it for my calculations and then discard it.

I suppose also, if you want to get a little more sophisticated you can try to increase your stack size. I know how to do that in assembly language, but I'm not sure about the various C compilers. Microsoft no doubt has some pragmas that support it and maybe gcc does to. Unfortunately MS has decided in recent versions of their compilers that inline assembly is simply not necessary any more.

Originally Posted by @nthony

uh... you mean to say *fully* compliant, right? because:
Quincy 99
Code::Blocks
Dev-C++
Pelles C
are all free, and all run on Windows.

quincy 99 is a bit obscure but I'd love to find out more about it. Is it a preprocessor that outputs C code? Is it fully C99 compliant eg VLAs and complex number support?

Dev-C++ will be gcc based and hence has their C99 limitations (eg no VLAs and no complex number support). By the way the reason why I want C99 complex number support is that a complex number is essentially double c[2] ; an array of 2 doubles. That plays nicely with Fortran which is why they chose this.

Pelles I am well aware of. It is missing several C99 features as well. VLAs are only partially supported, if they are dirt simple. I don't think for example you could dynamically allocate an array of pointers to some other complex type and I don't think it would allocate multidimensional arrays (not that I ever use C multi-D arrays.) Also of course, no one supports complex.

Originally Posted by Dave_Sinkula

http://www.peren.com/pages/cvsa_isocvpl.htm

Yup I've seen the list. Have you seen the price list? I think Dinkumware's C99 libraries are about $200 and then the front end from Edison Design costs some money, and then you still need a valid C89 compiler, which I suppose you could get for free. Then there is the cost of an IDE if you use that sort of thing and who knows if it plays nicely with C99 etc. etc.

In other words the support for C99 isn't exactly overwhelming.