Hello, On Mon, 8 Apr 2024 at 10:20, Matheus Afonso Martins Moreira via Gcc <gcc@gcc.gnu.org> wrote: > > I'd like to add GCC builtins for generating Linux system call > code for all architectures supported by Linux. > > They would look like this: > > __builtin_linux_system_call(long n, ...) > __builtin_linux_system_call_1(long n, long _1) > __builtin_linux_system_call_2(long n, long _1, long _2) > /* More definitions, all the way up to 6 arguments */
What's the advantage of the _1, _2 etc. forms? The compiler knows how many arguments you're passing, why can't there just be one built-in handling all cases? > > + It doesn't make sense for libraries to support it > > There are libraries out there that provide > system call functionality. The various libcs do. > However they usually don't support the full set > of Linux system calls. Using certain system calls > could invalidate global state in these libraries > which leads to them not being supported. Clone is > the quintessential example. So I think libraries > are not the proper place for this functionality. Your proposal doesn't seem to actually address the problem. If using the clone syscall causes problems for glibc by not giving glibc a chance to set up TLS etc for the new thread, how does making it easier to use the clone syscall help?
