I think adding a #define to define register to nothings makes sense.

If this is something that is tied to a specific C++ version, then it could be further qualified with a version value.

Mike

From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of pawel.karczewski via groups.io
Sent: Friday, February 16, 2024 2:00 AM
To: devel@edk2.groups.io
Subject: [edk2-devel] Using ekd2-libc with C++20

Hi,

I'm successfully building C++20 project with edk2 under the GCC compiler.
Currently I'm trying to add edk2-libc to this project, but encountered issue with <string.h> header.

```
edk2/StdLib/Include/string.h:487:19: error: ISO C++17 does not allow ‘register’ storage class specifier [-Werror=register] register char **stringp
```

Why `strsep(register char **stringp, register const char *delim)` parameters has register storage class-class specifier?
C standard states the `register` keyword is only hint for the compiler and the extent to which such
suggestions are effective is implementation-defined. Do you see any real performance improvements thanks to this?

As I can see FreeBSD libc and musl do not have `register` keyword in signature of this function.

How do you think, may we remove `register` keyword from headers in Include directory?

Second option I see is to add
```
#ifdef __cplusplus
#define register
#endif
```

Of course I may submit patch for this change.

Paweł



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