Enabling VLAs (variable length arrays) in MS Visual C++?

I met same problem, this is not possible in MS Visual C++ 2015, instead you can use vector to do almost the same, only difference is neglectable overhead of heap resource manage routine(new/delete).

Although VLAs is convenient, but to allocate non-deterministic amount of memory from the stack at risk of stack overflow is generally not a good idea.

MSVC is not a C99 compiler, and does not support variable length arrays.

At https://docs.microsoft.com/en-us/cpp/c-language/ansi-conformance MSVC is documented as conforming to C90.

VLA's are much neater to write but you can get similar behaviour using alloca() when the dynamic memory allocation of std::vector is prohibitive.

http://msdn.microsoft.com/en-us/library/x9sx5da1.aspx

Using alloca() in your example would give:

#include <stdlib.h>
#include <alloca.h>

int main(int argc, char **argv)
{
  char* pc = (char*) alloca(sizeof(char) * (argc+5));

  /* do something useful with pc */

  return EXIT_SUCCESS;
}