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Diffstat (limited to 'man2/_syscall.2')
| -rw-r--r-- | man2/_syscall.2 | 171 |
1 files changed, 0 insertions, 171 deletions
diff --git a/man2/_syscall.2 b/man2/_syscall.2 deleted file mode 100644 index 84612a1..0000000 --- a/man2/_syscall.2 +++ /dev/null @@ -1,171 +0,0 @@ -.\" Copyright (c) 1993 Michael Haardt (michael@moria.de), -.\" Fri Apr 2 11:32:09 MET DST 1993 -.\" -.\" SPDX-License-Identifier: GPL-2.0-or-later -.\" -.\" Tue Jul 6 12:42:46 MDT 1993 <dminer@nyx.cs.du.edu> -.\" Added "Calling Directly" and supporting paragraphs -.\" -.\" Modified Sat Jul 24 15:19:12 1993 by Rik Faith <faith@cs.unc.edu> -.\" -.\" Modified 21 Aug 1994 by Michael Chastain <mec@shell.portal.com>: -.\" Added explanation of arg stacking when 6 or more args. -.\" -.\" Modified 10 June 1995 by Andries Brouwer <aeb@cwi.nl> -.\" -.\" 2007-10-23 mtk: created as a new page, by taking the content -.\" specific to the _syscall() macros from intro(2). -.\" -.TH _syscall 2 2024-02-26 "Linux man-pages 6.7" -.SH NAME -_syscall \- invoking a system call without library support (OBSOLETE) -.SH SYNOPSIS -.nf -.B #include <linux/unistd.h> -.P -A _syscall macro -.P -desired system call -.fi -.SH DESCRIPTION -The important thing to know about a system call is its prototype. -You need to know how many arguments, their types, -and the function return type. -There are seven macros that make the actual call into the system easier. -They have the form: -.P -.in +4n -.EX -.RI _syscall X ( type , name , type1 , arg1 , type2 , arg2 ,...) -.EE -.in -.P -where -.IP -.I X -is 0\[en]6, which are the number of arguments taken by the -system call -.IP -.I type -is the return type of the system call -.IP -.I name -is the name of the system call -.IP -.I typeN -is the Nth argument's type -.IP -.I argN -is the name of the Nth argument -.P -These macros create a function called -.I name -with the arguments you -specify. -Once you include the _syscall() in your source file, -you call the system call by -.IR name . -.SH FILES -.I /usr/include/linux/unistd.h -.SH STANDARDS -Linux. -.SH HISTORY -Starting around Linux 2.6.18, the _syscall macros were removed -from header files supplied to user space. -Use -.BR syscall (2) -instead. -(Some architectures, notably ia64, never provided the _syscall macros; -on those architectures, -.BR syscall (2) -was always required.) -.SH NOTES -The _syscall() macros -.I "do not" -produce a prototype. -You may have to -create one, especially for C++ users. -.P -System calls are not required to return only positive or negative error -codes. -You need to read the source to be sure how it will return errors. -Usually, it is the negative of a standard error code, -for example, -.RI \- EPERM . -The _syscall() macros will return the result -.I r -of the system call -when -.I r -is nonnegative, but will return \-1 and set the variable -.I errno -to -.RI \- r -when -.I r -is negative. -For the error codes, see -.BR errno (3). -.P -When defining a system call, the argument types -.I must -be -passed by-value or by-pointer (for aggregates like structs). -.\" The preferred way to invoke system calls that glibc does not know -.\" about yet is via -.\" .BR syscall (2). -.\" However, this mechanism can be used only if using a libc -.\" (such as glibc) that supports -.\" .BR syscall (2), -.\" and if the -.\" .I <sys/syscall.h> -.\" header file contains the required SYS_foo definition. -.\" Otherwise, the use of a _syscall macro is required. -.\" -.SH EXAMPLES -.\" SRC BEGIN (_syscall.c) -.EX -#include <stdio.h> -#include <stdlib.h> -#include <errno.h> -#include <linux/unistd.h> /* for _syscallX macros/related stuff */ -#include <linux/kernel.h> /* for struct sysinfo */ -\& -_syscall1(int, sysinfo, struct sysinfo *, info); -\& -int -main(void) -{ - struct sysinfo s_info; - int error; -\& - error = sysinfo(&s_info); - printf("code error = %d\en", error); - printf("Uptime = %lds\enLoad: 1 min %lu / 5 min %lu / 15 min %lu\en" - "RAM: total %lu / free %lu / shared %lu\en" - "Memory in buffers = %lu\enSwap: total %lu / free %lu\en" - "Number of processes = %d\en", - s_info.uptime, s_info.loads[0], - s_info.loads[1], s_info.loads[2], - s_info.totalram, s_info.freeram, - s_info.sharedram, s_info.bufferram, - s_info.totalswap, s_info.freeswap, - s_info.procs); - exit(EXIT_SUCCESS); -} -.EE -.\" SRC END -.SS Sample output -.EX -code error = 0 -uptime = 502034s -Load: 1 min 13376 / 5 min 5504 / 15 min 1152 -RAM: total 15343616 / free 827392 / shared 8237056 -Memory in buffers = 5066752 -Swap: total 27881472 / free 24698880 -Number of processes = 40 -.EE -.SH SEE ALSO -.BR intro (2), -.BR syscall (2), -.BR errno (3) |