5 ms·
icc is arguably bigger than msvc (which is not even a modern C compiler)
by enriquto 6y ago
icc is arguably bigger than msvc (which is not even a modern C compiler)
- saagarjha 6y agoThankfully, it will be soon: https://devblogs.microsoft.com/cppblog/c11-and-c17-standard-support-arriving-in-msvc/ https://devblogs.microsoft.com/cppblog/c11-and-c17-standard-...
- enriquto 6y agohmmmm, no complex numbers, no vla... not really what many people call modern C nowadays.
- saagarjha 6y agoDo people actually use those?
- kevin_thibedeau 6y agoVLAs are a bad idea and nobody doing modern C should be touching them. It's alloca() magic and introduces all sorts of stack destroying risk.
- ChickeNES 6y agoIsn't there a plan to remove them in the next C standard?
- pjmlp 6y agoAlready done in C11, they were marked optional, so any compiler that jumped from C89 to C11 (we are on the edge of C2x now), isn't required to even bother themselves with VLAs and will still achieve C11 certification (C17, C2X,...)
- enriquto 6y agoPutting VLA in the stack is just an implementation choice. A conforming implementation could allocate all VLA in the heap (and freeing the memory upon scope loss), or do not even use a stack/heap system at all. In that sense, VLA are a crucial language feature to allow a RAII-style for C code. Essentially, you could replace this void f(int n, ...) { float *t = malloc(n * sizeof*t); // do stuff with t[i] free (t); } with the following semantically equivalent code void f(int n, ...) { float t[n]; // do stuff with t[i] } Today, this is not a good idea for large arrays because, unfortunately, many C implementations put VLA in the stack. I hope that by keeping VLA in the standard language, future C implementations will get to favor this usage. Notice that VLA are not more dangerous or risky than recursion. The exact same argument that you use against VLA can be used against recursion. Are you against recursive functions in C? Of course, you wouldn't traverse a long array using recursion, but if you are careful that the depth of recursion is logarithmic with the array size (e.g. as in binary search), then it is perfectly safe and reasonable to use recursion. The same thing with VLA. If you are sure that n is 2,3 or at most 4 there's no reason to avoid VLA due to stack scare, and they may make your code much simpler, clearer and better. On the other hand, VLA are useful even if you do not use them to allocate memory. Pointers to vla can be used for many things, for example accessing a one-dimensional array (allocated by a single call to malloc) using two indices as if it was a 2d array.
- pjmlp 6y agoGiven that they were removed from the standard, yes modern.
- TwoBit 6y agoWhat do you mean by icc being bigger?
- enriquto 6y agoit's an answer to the parent's claim that the "big" three compilers are gcc, clang and msvc. I guess they meant that in the sense of "the most relevant", or "the most used". While microsoft's is unarguably an important C++ compiler, it's rarely used for non-legacy C code.
- pjmlp 6y agoBecause C++ compilers aren't required to be C compilers as well. However they have backtracked on their position regarding supporting C on Windows, so latest MVSC does support C11 and C17.