SYSCALL(2) BSD System Calls Manual SYSCALL(2)
syscall - indirect system call
syscall(int number, ...);
Syscall() performs the system call whose assembly language interface has
the specified number with the specified arguments. Symbolic constants
for system calls can be found in the header file <sys/syscall.h>.
The return value is defined by the system call being invoked. In gen-
eral, a 0 return value indicates success. A -1 return value indicates an
error, and an error code is stored in errno.
There is no way to simulate system calls that have multiple return values
such as pipe(2).
The syscall() function call appeared in 4.0BSD.
4th Berkeley Distribution June 16, 1993 4th Berkeley Distribution