diff --git a/src/libCom/osi/epicsSignal.h b/src/libCom/osi/epicsSignal.h
index 0a2d84a46..cd53b1ef5 100644
--- a/src/libCom/osi/epicsSignal.h
+++ b/src/libCom/osi/epicsSignal.h
@@ -17,13 +17,22 @@ extern "C" {
 #include "shareLib.h"
 
 /* 
- * The requests in this interface are typically ignored outside of a POSIX
- * contex.
+ * The requests in this interface are typically ignored on OS that do not implement
+ * POSIX signals. 
  */
 
 struct epicsThreadOSD;
 
+/* 
+ * Required to avoid terminating a process which is blocking in a 
+ * socket send() call when the SIGPIPE signal is generated by the OS.
+ */
 epicsShareFunc void epicsShareAPI epicsSignalInstallSigPipeIgnore ( void );
+
+/* 
+ * required only if shutdown() and close() do not interrupt a thread blocking in
+ * a socket system call
+ */
 epicsShareFunc void epicsShareAPI epicsSignalInstallSigUrgIgnore ( void );
 epicsShareFunc void epicsShareAPI epicsSignalRaiseSigUrg ( struct epicsThreadOSD * );