How to silence Xcode warning: "variable length arrays are a C99 feature [-Wvla-extension]"?

Question

I am very confused by the format of Xcode, and have tried to look around to by advice: "invert the flag" that shows up when we get these warnings. If someone could walk me through how to get to that page to silence this warning. I would be VERY grateful :)

Re: `How to silence` - don't use them, they are not standard — Vlad Feinstein, Aug 13 '20 at 23:12
The best way is to remove variable length arrays. Go to your source code and replace the VLAs with `std::vector` — Thomas Sablik, Aug 13 '20 at 23:12
Closely related: [Why aren't variable-length arrays part of the C++ standard?](https://stackoverflow.com/questions/1887097/why-arent-variable-length-arrays-part-of-the-c-standard) I'm waffling over whether or not I should dupe-hammer, so I'll punt. — user4581301, Aug 13 '20 at 23:22
C++ does not support C99's variable length arrays. Use `std::vector`. — Eljay, Aug 13 '20 at 23:31

score 3 · Answer 1 · answered Aug 13 '20 at 23:38

You shouldn't use variable-length arrays. They are not a part of standard c++, and you should use a std::vector instead.

However, if you want to turn off a specific warning such as -Wvla-extension then you can explicitly suppress this warning by adding the -Wno-vla-extension flag when compiling the program.

You can add this flag to wherever you would normally put such flags in Xcode.

score 0 · Answer 2 · edited Aug 30 '21 at 14:01

I advise you to NOT use VLAs (variable Length Arrays) because they are out of the standard and unsafe, but if you know what you are doing, you can use

 #pragma clang diagnostic ignored "-Wwarning-name"

Replace warning-name with the warning name to silence

I assume you are using clang, but if you are using GCC, replace clang with GCC.

Here is a link may also help:

https://davedelong.com/blog/2018/12/15/silencing-specific-build-warnings/

How to silence Xcode warning: "variable length arrays are a C99 feature [-Wvla-extension]"?

2 Answers2