How to define syscall() in freebsd?

[Brian]

On Thursday, 12 July 2018 at 15:45:41 UTC, Joakim wrote:
> On Thursday, 12 July 2018 at 13:55:58 UTC, Brian wrote:
>> the code is error:
>> extern (C) nothrow @nogc size_t syscall(size_t ident);
>> extern (C) nothrow @nogc size_t syscall(size_t ident, size_t 
>> arg0);
>> extern (C) nothrow @nogc size_t syscall(size_t ident, long* 
>> arg0);
>>
>> long tid;
>> syscall(SYS_thr_self, &tid);
>> writeln(tid);
>>
>> Error: Function type does not match previously declared 
>> function with the same mangled name: syscall
>
> Just like in C, you cannot declare multiple extern(C) functions 
> with the same name.
>
>> Change to:
>> extern (C) nothrow @nogc size_t syscall(size_t ident);
>> extern (C) nothrow @nogc size_t syscall(size_t ident, size_t 
>> arg0);
>> extern (C) nothrow @nogc size_t syscall(size_t ident, long* 
>> arg0);
>>
>> long tid;
>> syscall(SYS_thr_self, &tid);
>> writeln(tid);
>
> What did you change? I see no difference.
>
>> Error: none of the overloads of syscall are callable using 
>> argument types (int, long*), candidates are:
>> source/app.d(3,33):        kiss.sys.syscall.syscall(ulong 
>> ident)
>> source/app.d(4,33):        kiss.sys.syscall.syscall(ulong 
>> ident, ulong arg0)
>
> Look at the types: the error says you're passing an int and 
> long* on 64-bit to functions with different types.
>
>> Change to:
>> // extern (C) nothrow @nogc size_t syscall(size_t ident);
>> // extern (C) nothrow @nogc size_t syscall(size_t ident, 
>> size_t arg0);
>> extern (C) nothrow @nogc size_t syscall(size_t ident, long* 
>> arg0);
>>
>> long tid;
>> syscall(SYS_thr_self, &tid);
>> writeln(tid);
>>
>> result:
>>
>> 100567
>
> Probably related to first issue mentioned- you cannot overload 
> C functions- maybe the compiler finds the third now that you 
> removed the disallowed overloads.

I'm sorry, downstairs:
the code is error:
extern (C) nothrow @nogc size_t syscall(size_t ident);
extern (C) nothrow @nogc size_t syscall(size_t ident, size_t 
arg0);
extern (C) nothrow @nogc size_t syscall(size_t ident, long* arg0);

long tid;
syscall(SYS_thr_self, &tid);
writeln(tid);

Error: Function type does not match previously declared function 
with the same mangled name: syscall


Change to:
extern (C) nothrow @nogc size_t syscall(size_t ident);
extern (C) nothrow @nogc size_t syscall(size_t ident, size_t 
arg0);

long tid;
syscall(SYS_thr_self, &tid);
writeln(tid);

Error: none of the overloads of syscall are callable using 
argument types (int, long*), candidates are:
source/app.d(3,33):        kiss.sys.syscall.syscall(ulong ident)
source/app.d(4,33):        kiss.sys.syscall.syscall(ulong ident, 
ulong arg0)

freebsd syscall()
https://www.freebsd.org/cgi/man.cgi?query=syscall&sektion=2

How to define it in D?