<s>
The	O
Microsoft	B-Library
Layer	I-Library
for	I-Library
Unicode	I-Library
(	O
MSLU	B-Library
)	O
is	O
a	O
software	B-Library
library	I-Library
for	O
legacy	O
versions	O
of	O
Windows	O
,	O
simplifying	O
the	O
creation	O
of	O
Unicode-aware	O
programs	O
on	O
Windows	O
9x	O
(	O
Windows	B-Application
95	I-Application
,	O
Windows	B-Device
98	I-Device
,	O
and	O
Windows	B-Device
Me	I-Device
)	O
.	O
</s>
<s>
It	O
is	O
also	O
known	O
as	O
UnicoWS	B-Library
(	O
Unicode	O
for	O
Windows	O
95/98/Me	O
Systems	O
)	O
or	O
by	O
its	O
filename	B-Device
,	O
.	O
</s>
<s>
Microsoft	O
described	O
it	O
as	O
providing	O
"	O
a	O
layer	O
over	O
the	O
Win32	B-Library
API	I-Library
on	O
Windows	O
95/98/Me	O
so	O
that	O
a	O
software	O
developer	O
can	O
write	O
a	O
single	O
Unicode	O
version	O
of	O
their	O
application	O
and	O
have	O
it	O
run	O
properly	O
on	O
all	O
platforms.	O
"	O
</s>
<s>
Previously	O
,	O
developers	O
had	O
to	O
either	O
provide	O
two	O
separate	O
versions	O
of	O
an	O
application	O
,	O
or	O
perform	O
complex	O
string	O
translations	O
and	O
API	B-General_Concept
decisions	O
at	O
runtime	O
.	O
</s>
<s>
In	O
the	O
present	O
,	O
UnicoWS	B-Library
can	O
be	O
used	O
to	O
compile	O
newer	O
software	O
,	O
which	O
often	O
expects	O
Unicode	O
support	O
,	O
(	O
partially	O
due	O
to	O
the	O
influential	O
"	O
UTF-8	O
Everywhere	O
"	O
manifesto	O
,	O
)	O
for	O
legacy	O
versions	O
of	O
Windows	O
.	O
</s>
<s>
UnicoWS	B-Library
can	O
also	O
be	O
used	O
at	O
link	B-Application
time	I-Application
to	O
compile	O
software	O
in	O
languages	O
that	O
did	O
not	O
exist	O
contemporaneously	O
with	O
Windows	O
9x	O
and	O
require	O
Unicode	O
support	O
,	O
like	O
Rust	B-Application
.	O
</s>
<s>
Alternatives	O
exist	O
,	O
among	O
them	O
,	O
""	O
,	O
an	O
abandonware	O
yet	O
free	B-Application
(	O
MPL	O
1.1/GPL	O
2.0/LGPL	O
2.1	O
licensed	O
)	O
re-implementation	O
of	O
the	O
MSLU	B-Library
by	O
Mozilla	B-Operating_System
.	O
</s>
<s>
The	O
MSLU	B-Library
was	O
announced	O
in	O
March	O
2001	O
,	O
and	O
was	O
first	O
made	O
available	O
as	O
a	O
compatibility	B-General_Concept
layer	I-General_Concept
for	O
Unicode-supporting	O
code	O
written	O
for	O
the	O
then-new	O
Windows	B-Application
XP	I-Application
RC1	I-Application
in	O
the	O
July	O
2001	O
edition	O
of	O
Microsoft	O
's	O
Platform	B-Application
SDK	I-Application
.	O
</s>
<s>
This	O
drew	O
criticism	O
from	O
developers	O
who	O
feel	O
it	O
was	O
"	O
too	O
late	O
"	O
,	O
as	O
it	O
was	O
released	O
long	O
past	O
the	O
peak	O
popularity	O
of	O
Windows	O
9x	O
and	O
only	O
one	O
month	O
before	O
the	O
release	O
to	O
manufacturing	O
of	O
Windows	B-Application
XP	I-Application
.	O
</s>
<s>
MSLU	B-Library
was	O
given	O
the	O
codename	B-General_Concept
Godot	O
,	O
a	O
reference	O
to	O
Waiting	O
for	O
Godot	O
,	O
a	O
play	O
centered	O
around	O
the	O
failure	O
of	O
a	O
man	O
named	O
"	O
Godot	O
"	O
to	O
arrive	O
and	O
the	O
endless	O
wait	O
for	O
him	O
,	O
because	O
such	O
a	O
Unicode	O
compatibility	B-General_Concept
layer	I-General_Concept
was	O
thought	O
—	O
even	O
inside	O
Microsoft	O
—	O
to	O
have	O
been	O
long	O
overdue	O
.	O
</s>
<s>
Normally	O
,	O
the	O
Windows	B-Library
API	I-Library
provides	O
both	O
(	O
ANSI	O
escape	O
codes	O
and	O
ASCII	B-Protocol
characters	I-Protocol
)	O
and	O
(	O
"	B-Language
wide	I-Language
"	I-Language
character	I-Language
)	O
versions	O
of	O
most	O
subroutines	O
.	O
</s>
<s>
On	O
the	O
Windows	B-Device
NT	I-Device
line	O
of	O
operating	O
systems	O
,	O
both	O
the	O
and	O
versions	O
are	O
implemented	O
(	O
however	O
,	O
the	O
operating	O
system	O
generally	O
only	O
internally	O
implements	O
the	O
version	O
natively	O
,	O
and	O
the	O
version	O
is	O
usually	O
a	O
translation	O
thunk	B-Application
to	O
the	O
version	O
)	O
.	O
</s>
<s>
By	O
adding	O
the	O
to	O
the	O
link	O
command-line	O
before	O
,	O
,	O
or	O
any	O
other	O
supported	O
Win32	B-Library
system	O
link	O
library	O
,	O
the	O
linker	O
will	O
resolve	O
referenced	O
symbols	O
with	O
the	O
ones	O
provided	O
by	O
instead	O
.	O
</s>
<s>
If	O
so	O
,	O
it	O
dynamically	O
loads	O
(	O
if	O
it	O
has	O
n't	O
been	O
loaded	O
yet	O
)	O
and	O
passes	O
control	O
to	O
the	O
corresponding	O
thunking	B-Application
stub	O
in	O
there	O
.	O
</s>
<s>
The	O
thunking	B-Application
stub	O
translates	O
the	O
wide-character	O
arguments	O
into	O
ANSI	O
strings	O
and	O
then	O
invokes	O
the	O
native	O
version	O
from	O
the	O
OS	O
,	O
and	O
translates	O
any	O
returned	O
strings	O
back	O
into	O
wide	B-Language
character	I-Language
format	O
.	O
</s>
<s>
the	O
Windows	B-Device
NT	I-Device
line	O
of	O
operating	O
systems	O
)	O
,	O
then	O
the	O
function	O
stub	O
updates	O
the	O
in-memory	O
symbol	B-Application
table	I-Application
so	O
that	O
future	O
calls	O
will	O
directly	O
invoke	O
the	O
native	O
version	O
without	O
any	O
more	O
overhead	O
.	O
</s>
<s>
Because	O
of	O
this	O
technique	O
,	O
when	O
an	O
application	O
is	O
linked	O
against	O
MSLU	B-Library
,	O
only	O
Windows	O
95/98/Me	O
systems	O
will	O
need	O
to	O
rely	O
on	O
at	O
runtime	O
,	O
and	O
on	O
all	O
other	O
versions	O
of	O
Windows	O
there	O
is	O
only	O
a	O
slight	O
performance	O
penalty	O
the	O
first	O
time	O
a	O
function	O
is	O
called	O
.	O
</s>
<s>
A	O
common	O
problem	O
encountered	O
occurs	O
when	O
some	O
update	O
packages	O
or	O
uninstall	O
programs	O
rename	O
or	O
delete	O
either	O
of	O
the	O
OLE	B-Operating_System
libraries	O
(	O
,	O
)	O
,	O
which	O
are	O
dependencies	O
of	O
.	O
</s>
<s>
This	O
results	O
in	O
some	O
applications	O
,	O
such	O
as	O
OpenOffice.org,	O
showing	O
an	O
error	O
with	O
the	O
message	O
"	O
Application	O
cannot	O
start	O
because	O
one	O
of	O
the	O
required	O
libraries	O
cannot	O
be	O
found.	O
"	O
</s>
<s>
This	O
occurs	O
even	O
if	O
is	O
installed	O
in	O
the	O
system	O
,	O
as	O
it	B-Protocol
cannot	I-Protocol
start	I-Protocol
without	I-Protocol
its	I-Protocol
dependencies	I-Protocol
(	O
see	O
also	O
DLL	O
hell	O
)	O
.	O
</s>
