syscall.2

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 2 代码 · 共 42 行

.\" SCCSID: @(#)syscall.2	8.1	9/11/90
.TH syscall 2 VAX
.SH Name
syscall \- indirect system call
.SH Syntax
.nf
.BR "syscall(number, arg, ...)" 
.fi
.SH Description
.NXR "syscall system call"
.NXR "system call" "performing indirect"
The
.PN syscall
system call
performs the system call whose assembly language
interface has the specified
.I number,
register arguments
.I r0
and
.IR r1 ,
and further arguments
.IR arg .
.PP
The 
.I r0 
value of the system call is returned.
.SH Restrictions
There is no way to simulate system calls
such as 
.PN pipe ,
which return values in register 
.IR r1 .
.SH Diagnostics
When the C-bit is set,
.PN syscall
returns \-1 and sets the
external variable 
.I errno.
.SH See Also
errno(2), pipe(2)