getsysinfo.2

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 2 代码 · 共 138 行

.\" SCCSID: @(#)getsysinfo.2	2.3	5/19/87
.TH getsysinfo 2
.SH Name
getsysinfo \- get system information
.SH Syntax
.nf
#include <sys/types.h>
#include <sys/sysinfo.h>
.PP
getsysinfo(\fIop, buffer, nbytes, start, arg\fP)
unsigned	\fIop\fP;
char		*\fIbuffer\fP;
unsigned	 \fInbytes\fP;	
int 		*\fIstart\fP;
char		 *\fIarg\fP;	
.fi
.SH Description
.NXR "getsysinfo system call"
The
.PN getsysinfo
system call retrieves information from the system.
.PP
The
.I op
argument specifies the operation to be performed.  
Values for 
.I op
are defined in the <sys/sysinfo.h> header file. 
.PP
Possible 
.I op
values are as follows:
.IP "GSI_BOOTDEV" 0.3i
Return the BOOTDEV string, which is used for the installation.
.IP "GSI_NETBLK" 0.3i
Return the entire NETBLK structure, which is used for the network
installation.
.IP "GSI_PROG_ENV" 0.3i
Return the compatibility mode of the process.  Possible values are
A_BSD, A_POSIX, A_SYSTEM_FIVE as defined in <sys/exec.h>.
.IP "GSI_MAX_UPROCS"
Return the maximum number of processes allowed per user id.
.IP "GSI_TTYP"
Return the major and minor numbers of the controlling terminal.
.IP "GSI_UACSYS (RISC only)"
Return current value of flag that determines whether or not to
print "unaligned access fixup" message on a system-wide basis.
.IP "GSI_UACPARNT (RISC only)"
Return current value of flag in parent process's structure for
printing unaligned access messages.
.IP "GSI_UACPROC (RISC only)"
Return current value of flag in process's structure for printing of
unaligned access messages.
.IP "GSI_MMAP_ALIGNMENT (RISC only)"
Return the minimum alignment required for an address specified with the
.PN MAP_FIXED
option in the
.PN mmap(2)
system call.
.PP
The
.I nbytes
argument defines the size of
.IR buffer 
into which the system information is returned.
.PP
The
.I start
argument is the current logical location within the internal system
table referenced by the op, and it must be initially set to
.PN 0 .
The 
.I start
argument is updated to reflect the current logical
location within the system table,
allowing successive executions of
.PN getsysinfo
to retrieve information about all the system structures specified by op.
.PP
The 
.I start
argument is set to 0 when all system information requested by
.I op
has been retrieved.
.PP
The optional
.I arg
argument may be used by certain 
.I op's 
for additional information.
When 
.I arg 
is not required, it should be set to NULL.
.PP
When information about multiple 
system structures is returned,
it is stored within consecutive 
.I buffer
locations. 
The information for each system structure is 
dependent upon
.I op.
.EE
.SH Return Values
.PP
Upon successful completion, a value indicating the number of
requested items
stored in
.I buffer
is returned.
If the information requested by 
.I op
is not available,
.I getsysinfo
returns a zero.
Otherwise, \-1 is returned, and the global variable,
.PN errno ,
is set to indicate the error.
.SH Diagnostics
.TP 15
[EFAULT]
Either
.I buffer,
.I start,
or
.I arg
causes an illegal address to be referenced.
.TP 15
[EINVAL]
The 
.I op
argument is invalid.
.TP 15
[EPERM]
Permission is denied for the operation requested
.SH See Also
setsysinfo(2)