<s>
Synchronous	O
Interprocess	O
Messaging	O
Project	O
for	O
LINUX	B-Application
(	O
SIMPL	B-Operating_System
)	O
is	O
a	O
free	B-License
and	I-License
open-source	I-License
project	O
that	O
allows	O
QNX-style	O
synchronous	O
message	O
passing	O
by	O
adding	O
a	O
Linux	B-Application
library	O
using	O
user	B-Operating_System
space	I-Operating_System
techniques	O
like	O
shared	O
memory	O
and	O
Unix	O
pipes	O
to	O
implement	O
SendMssg/ReceiveMssg/ReplyMssg	O
inter-process	O
messaging	O
mechanisms	O
.	O
</s>
<s>
SIMPL	B-Operating_System
does	O
not	O
appear	O
to	O
be	O
thread	O
safe	O
.	O
</s>
<s>
There	O
is	O
one	O
other	O
QNX-inspired	O
synchronous	O
message	O
passing	O
projects	O
available	O
for	O
Linux	B-Application
.	O
</s>
<s>
SRR	B-Operating_System
IPC	I-Operating_System
(	O
for	O
Send/Receive/Reply	O
)	O
by	O
Sam	O
Roberts	O
and	O
Andrew	O
Thomas	O
of	O
which	O
is	O
related	O
to	O
the	O
SIMPL	B-Operating_System
project	O
and	O
adds	O
a	O
QNX-compatible	O
API	O
layer	O
.	O
</s>
<s>
SRR	O
is	O
a	O
loadable	B-Application
kernel	I-Application
module	I-Application
designed	O
to	O
be	O
QNX	B-Operating_System
API	O
compatible	O
to	O
facilitate	O
porting	O
of	O
code	O
.	O
</s>
