Date: Mon, 06 Nov 2000 11:52:19 -0500 From: Raymond Law <rlaw@vt.edu> To: freebsd-questions@FreeBSD.ORG Subject: system call and SYSCALL macro Message-ID: <4.3.0.20001106114918.01cc6bb0@mail.vt.edu>
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Hi:
I am trying to implement a system call. I used the
syscalls.master already. I know I have to modify libc, but this requires
makeworld and all the binaries must be compiled again. If I don't want to
modify libc, I know I have to use the SYSCALL macro or something like
that. But I don't know how to use it. Also, I tried the syscall()
function but are not getting good results.
I just try to add a simple system call for testing:
int my_call(int x, int y) {
return (x + y);
}
In my user program:
int main(int argc, char ** argv) {
int x = 3;
int y = 8;
int z = 0;
z = syscall(SYS_my_call, x, y);
printf("%i + %i = %i\n", x, y, z);
return 0;
}
But it prints:
3 + 8 = -1
Can you give me some idea what I did wrong and what I should do? Also, can
you tell me how to use the SYSCALL macro because I am not familiar with
macros at all? Thanks in advance.
Thanks.
Ray,
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