man2/syscall.2

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  32 .\"     @(#)syscall.2   8.1 (Berkeley) 6/16/93
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  35 .\" 2002-03-20  Christoph Hellwig <hch@infradead.org>
  36 .\"     - adopted for Linux
  37 .\"
  38 .Dd June 16, 1993
  39 .Dt SYSCALL 2
  40 .Os BSD 4
  41 .Sh NAME
  42 .Nm syscall
  43 .Nd indirect system call
  44 .Sh SYNOPSIS
  45 .Fd #include <sys/syscall.h>
  46 .Fd #include <unistd.h>
  47 .Ft int
  48 .Fn syscall "int number" "..."
  49 .Sh DESCRIPTION
  50 .Fn Syscall
  51 performs the system call whose assembly language
  52 interface has the specified
  53 .Fa number
  54 with the specified arguments.
  55 Symbolic constants for system calls can be found in the header file
  56 .Ao Pa sys/syscall.h Ac .
  57 .Sh RETURN VALUES
  58 The return value is defined by the system call being invoked.
  59 In general, a 0 return value indicates success.
  60 A -1 return value indicates an error,
  61 and an error code is stored in
  62 .Va errno .
  63 .Sh BUGS
  64 There is no way to simulate system calls that have multiple return values
  65 such as
  66 .Xr pipe 2 .
  67 .Sh HISTORY
  68 The
  69 .Fn syscall
  70 function call appeared in
  71 .Bx 4.0 .
  72 .\" dummy comment without newline