stack-size option ignored by g++-9

[Paul Jurczak]

I was encouraged to repost my stackoverflow question here (https://stackoverflow.com/questions/61709726). In case stack-size option is not implemented for this particular environment, a warning would be helpful.

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I'm building a test program with g++ 9.3.0 on Ubuntu 18.04 x64 using this linker command:

/usr/bin/g++-9 -O3 -DNDEBUG -Wl,-z,stack-size=268435456 CMakeFiles/af.dir/main.cpp.o -o af

I'm testing increased stack requirements with this function:

float f() {
  float a[3'000'000];
  return a[42];
}

and results indicate a standard 8MB stack regardless of the stack-size linker option value. What is the way to increase the stack size?

EDIT

The test is as follows:

float a[3'000'000]; causes Segmentation fault (core dumped)
float a[2'000'000]; returns 0 as expected