.\"-
.\" Copyright (c) 2001 Chris D. Faulhaber
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.Dd March 13, 2001
.Dt ACL_GET_QUALIFIER 3
.Os
.Sh NAME
.Nm acl_get_qualifier
.Nd retrieve the qualifier from an ACL entry
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/types.h
.In sys/acl.h
.Ft void *
.Fn acl_get_qualifier "acl_entry_t entry_d"
.Sh DESCRIPTION
The
.Fn acl_get_qualifier
function
is a POSIX.1e call that retrieves the qualifier of the tag for
the ACL entry indicated by the argument
.Fa entry_d
into working storage and returns a pointer to that storage.
.Pp
If the value of the tag type in the ACL entry referred to by
.Fa entry_d
is
.Dv ACL_USER ,
then the value returned by
.Fn acl_get_qualifier
will be a pointer to type
.Vt uid_t .
.Pp
If the value of the tag type in
the ACL entry referred to by
.Fa entry_d
is
.Dv ACL_GROUP ,
then the value returned by
.Fn acl_get_qualifier
will be a pointer to type
.Vt gid_t .
.Pp
If the value of the tag type in the ACL entry referred to by
.Fa entry_d
is
.Dv ACL_UNDEFINED_TAG , ACL_USER_OBJ , ACL_GROUP_OBJ ,
.Dv ACL_OTHER , ACL_MASK ,
or an implementation-defined value for which a qualifier
is not supported, then
.Fn acl_get_qualifier
will return a value of
.Vt ( void * ) Ns Dv NULL
and the function will fail.
.Pp
This function may cause memory to be allocated.
The caller should
free any releasable memory, when the new qualifier is no longer
required, by calling
.Fn acl_free
with
.Vt void *
as the argument.
.Sh RETURN VALUES
The
.Fn acl_get_qualifier
function returns a pointer to the allocated storage if successful;
otherwise a
.Dv NULL
pointer is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
The
.Fn acl_get_qualifier
fails if:
.Bl -tag -width Er
.It Bq Er EINVAL
Argument
.Fa entry_d
does not point to a valid descriptor for an ACL entry.
The
value of the tag type in the ACL entry referenced by argument
.Fa entry_d
is not
.Dv ACL_USER
or
.Dv ACL_GROUP .
.It Bq Er ENOMEM
The value to be returned requires more memory than is allowed
by the hardware or system-imposed memory management constraints.
.El
.Sh SEE ALSO
.Xr acl 3 ,
.Xr acl_create_entry 3 ,
.Xr acl_free 3 ,
.Xr acl_get_entry 3 ,
.Xr acl_get_tag_type 3 ,
.Xr acl_set_qualifier 3 ,
.Xr acl_set_tag_type 3 ,
.Xr posix1e 3
.Sh STANDARDS
POSIX.1e is described in IEEE POSIX.1e draft 17.
.Sh HISTORY
POSIX.1e support was introduced in
.Fx 4.0 .
The
.Fn acl_get_qualifier
function was added in
.Fx 5.0 .
.Sh AUTHORS
The
.Fn acl_get_qualifier
function was written by
.An Chris D. Faulhaber Aq jedgar@fxp.org .