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.Dd May 11, 2016
.Dt PLDT 3PROC
.Os
.Sh NAME
.Nm Pldt ,
.Nm proc_get_ldt
.Nd obtain local descriptor table of a process
.Sh SYNOPSIS
.Lb libproc
.In libproc.h
.Ft int
.Fo Pldt
.Fa "struct ps_prochandle *P"
.Fa "struct ssd *pldt"
.Fa "int nldt"
.Fc
.Ft int
.Fo proc_get_ldt
.Fa "pid_t pid"
.Fa "struct ssd *pldt"
.Fa "int nldt"
.Fc
.Sh DESCRIPTION
The
.Fn Pldt
function reads the local descriptor table (LDT) of the process handle
.Fa P
into the buffer
.Fa pldt .
Up to
.Fa nldt
entries will be read.
.Pp
If either
.Fa pldt
is
.Dv NULL
or
.Fa nldt
is
.Fa 0 ,
then rather than filling in
.Fa pldt ,
only the number of entries currently in the LDT is returned.
.Pp
The buffer
.Fa pldt
should contain sufficient space for
.Fa nldt
entries.
For example, callers could allocate space as:
.Pp
.Dl pldt = malloc(sizeof (struct ssd) * nldt);
.Pp
For more information on the LDT and the
.Sy struct ssd ,
see
.Xr proc 4 .
.Pp
The
.Fn proc_get_ldt
function is similar to the
.Fn Pldt
function; however, rather than reading from a process handle, it reads
the
.Sy ldt
file from the /proc file system for the process
.Fa pid .
.Sh RETURN VALUES
Upon successful completion, the
.Fn Pldt
and
.Fn proc_get_ldt
functions return the number of LDT entries written to
.Fa pldt .
If
.Fa pldt
is
.Dv NULL
or
.Fa nldt
is zero, then no data will be written.
Otherwise,
.Sy -1
is returned.
The
.Fn Pldt
function sets
.Sy errno
to indicate the error that occurred.
.Sh ERRORS
For a full list of possible errors see the
.Sy DIAGNOSTICS
section in
.Xr proc 4 .
.Pp
The
.Fn Pldt
function will fail if:
.Bl -tag -width Er
.It Er ENODATA
No LDT information is available in the process handle
.Fa P .
.El
.Sh ARCHITECTURE
The
.Fn Pldt
and
.Fn proc_get_ldt
functions are only available on
.Sy x86
platforms.
.Sh INTERFACE STABILITY
.Sy Uncommitted
.Sh MT-LEVEL
See
.Sy LOCKING
in
.Xr libproc 3LIB .
.Sh SEE ALSO
.Xr libproc 3LIB ,
.Xr proc 4