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SYSCALL(2)		  FreeBSD System Calls Manual		    SYSCALL(2)

NAME
     syscall, __syscall	-- indirect system call

LIBRARY
     Standard C	Library	(libc, -lc)

SYNOPSIS
     #include <sys/syscall.h>
     #include <unistd.h>

     int
     syscall(int number, ...);

     off_t
     __syscall(quad_t number, ...);

DESCRIPTION
     The syscall() function performs the system	call whose assembly language
     interface has the specified number	with the specified arguments.  Sym-
     bolic constants for system	calls can be found in the header file
     <sys/syscall.h>.  The __syscall() form should be used when	one or more of
     the arguments is a	64-bit argument	to ensure that argument	alignment is
     correct.  This system call	is useful for testing new system calls that do
     not have entries in the C library.

RETURN VALUES
     The return	values are 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.

HISTORY
     The syscall() function appeared in	4.0BSD.

BUGS
     There is no way to	simulate system	calls that have	multiple return	values
     such as pipe(2).

FreeBSD	10.1			 June 16, 1993			  FreeBSD 10.1

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | HISTORY | BUGS

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