bsd/man/man2/syscall.2

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  34 .\"     @(#)syscall.2   8.1 (Berkeley) 6/16/93
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  36 .Dd June 23, 2008
  37 .Dt SYSCALL 2
  38 .Os BSD 4
  39 .Sh NAME
  40 .Nm syscall
  41 .Nd indirect system call
  42 .Sh SYNOPSIS
  43 .Fd #include <sys/syscall.h>
  44 .Fd #include <unistd.h>
  45 .Ft int
  46 .Fn syscall "int number" "..."
  47 .Sh DESCRIPTION
  48 .Fn syscall
  49 performs the system call whose assembly language
  50 interface has the specified
  51 .Fa number
  52 with the specified arguments.
  53 Symbolic constants for system calls can be found in the header file
  54 .Ao Pa sys/syscall.h Ac .
  55 This function is useful for testing new system calls that
  56 do not have entries in the C library.
  57 .Sh RETURN VALUES
  58 The return values are 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 .