references #271: correctly interpreting return values and errno of ib verb functions

ibvla/src/common/Utils.cc

@@ -41,7 +41,23 @@ std::list<ibvla::Device> ibvla::getDeviceList ()
 	if (devlist == 0)
 	{
 		std::stringstream ss;
-		ss << "Failure to get device list, errno = " << ::strerror(errno);
+		ss << "Failed to get device list: ";
+		if (errno == EPERM)
+		{
+			ss << "Permission denied, " << strerror(errno) << "(" << errno << ")";
+		}
+		else if (errno == ENOMEM)
+		{
+			ss << "Insufficient memory to complete the operation, " << strerror(errno) << "(" << errno << ")";
+		}
+		else if (errno == ENOSYS)
+		{
+			ss << "No kernel support for RDMA, " << strerror(errno) << "(" << errno << ")";
+		}
+		else
+		{
+			ss << "Not understood error, errno = " << errno;
+		}
 		XCEPT_RAISE(ibvla::exception::Exception, ss.str());
 	}