MODIFY_LDT
Section: Linux Programmer's Manual (2)
Updated: 22 July 1995
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NAME
modify_ldt - get or set ldt
SYNOPSIS
#include <linux/ldt.h>
#include <linux/unistd.h>
_syscall3( int, modify_ldt, int, func, void *, ptr, unsigned long, bytecount )
int modify_ldt(int func, void *ptr, unsigned long bytecount);
DESCRIPTION
modify_ldt
reads or writes the local descriptor table (ldt) for a process.
The ldt is a per-process memory management table used by the i386 processor.
For more information on this table, see an Intel 386 processor handbook.
When
func
is 0,
modify_ldt
reads the ldt into the memory pointed to by
ptr.
The number of bytes read is the smaller of
bytecount
and the actual size of the ldt.
When
func
is 1,
modify_ldt
modifies one ldt entry.
ptr
points to a
modify_ldt_ldt_s
structure and
bytecount
must equal the size of this structure.
RETURN VALUE
On success,
modify_ldt
returns either the actual number of bytes read (for reading)
or 0 (for writing).
On failure,
modify_ldt
returns -1 and sets
errno.
ERRORS
- ENOSYS
-
func
is neither 0 nor 1.
- EINVAL
-
ptr
is 0,
or
func
is 1 and
bytecount
is not equal to the size of the structure
modify_ldt_ldt_s,
or
func
is 1 and the new ldt entry has illegal values.
- EFAULT
-
ptr
points outside the address space.
SEE ALSO
vm86(2)
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- SEE ALSO
-
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