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1 | .\" Copyright (c) 1980 Regents of the University of California. |
2 | .\" All rights reserved. The Berkeley software License Agreement | |
3 | .\" specifies the terms and conditions for redistribution. | |
4 | .\" | |
cdd5eb15 | 5 | .\" @(#)syscall.2 6.2 (Berkeley) %G% |
695ad0b4 | 6 | .\" |
f9effee3 | 7 | .TH SYSCALL 2 "" |
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8 | .UC 4 |
9 | .SH NAME | |
10 | syscall \- indirect system call | |
11 | .SH SYNOPSIS | |
12 | .nf | |
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13 | .ft B |
14 | #include <syscall.h> | |
15 | .PP | |
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16 | .BR "syscall(number, arg, ...)" \ \ (VAX-11) |
17 | .fi | |
18 | .SH DESCRIPTION | |
19 | .I Syscall | |
20 | performs the system call whose assembly language | |
21 | interface has the specified | |
22 | .I number, | |
23 | register arguments | |
24 | .I r0 | |
25 | and | |
26 | .I r1 | |
92a92bd0 | 27 | and further arguments |
695ad0b4 | 28 | .IR arg . |
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29 | Symbolic constants for system calls can be found in the header file |
30 | .I <syscall.h>. | |
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31 | .PP |
32 | The r0 value of the system call is returned. | |
33 | .SH DIAGNOSTICS | |
34 | When the C-bit is set, | |
35 | .I syscall | |
36 | returns \-1 and sets the | |
37 | external variable | |
38 | .I errno | |
39 | (see | |
40 | .IR intro (2)). | |
41 | .SH BUGS | |
42 | There is no way to simulate system calls | |
43 | such as | |
44 | .IR pipe (2), | |
45 | which return values in register r1. |