#include <config.h>
#include <CPortManager.h>
#include <CPortManagerException.h>
classCPortManager{CPortManager(std::string host = string("localhost"));CPortManager(std::string host, int Port);int allocatePort(std::string application);std::vector<portInfo> getPortUsage();};
CPortManager
provides a C++ application programming interface into the NSCL
port manager server. This class serves as a proxy for communication with port
management servers. Once you have created a
CPortManager object, you can use
it to allocate ports (if the server is local), and to list port usage of any
server on the network.
Note that members of this class can throw exceptions of type
CPortManagerException.
See the CPortManagerException(3) for
more informationa bout that.
To include the headers required you, or the Makefile skeleton you are using must have added the include subdirectory ofthe NSCLDAQ installation directory tree to the include paths for the compile e.g.: -I/usr/opt/daq/current/include.
To link you must include the NSCL DAQ lib subdirectory in the library search path, link in the library and ensure that the shared library can be found at load time. For example:
-L/usr/opt/daq/current/lib \
-lPortManager \
-Wl,"-rpath=/usr/opt/daq/current/lib"
CPortManager(std::string host = string("localhost"));
Constructs a port manager interface object. The object connects to the
port manager running on the host host, using the
default port (30000) to form the connection. If the
host parameter is omitted, it defaults to
localhost
CPortManager(std::string host, int Port);
Constructs a port manager interfaceobject. The object connects
to the host manager running on host via the
connection port Port.
int allocatePort(std::string application);
Allocates a port from the port manager. On success the return value is the port number allocated in local machine byte order. Note that when interacting with the network functions, in general, this will have to be converted to network byte ordering.
Once the port is allocated, it remains allocated until the program exits. This is because a connection will be held with the port manager and cannot be closed by the user.
If a port could not be allocated (e.g. all are in use or the port manager could
not be contacted, a CPortManagerException described
in "Types and public data" below and completely in
CPortManagerException.
std::vector<portInfo> getPortUsage();
Returns a vector of portInfo structs that describes the current port allocations of the port allocator. The most common use case for this is to locate a specific service offered by a remote port manager.
If the interaction with the server failed,
a CPortManagerException described
in "Types and public data" below and completely in
CPortManagerException.
The set of port allocations is described by an STL vector of
portInfo structs. The std::vector
is described in any C++ reference that contains a description of the Standard
Template Library (STL).
portInfo structs have the following fields:
Type: int
Name: s_Port
Description: The port number that this object describes. The port number is provided in the byte order of the local system. Note that when used to provide a port number to Unix/Linux network functions in general this number will have to be converted to network byte order.
Type: std::string
Name: s_Application
Description:
The name of the application that requested this port. The application
name represents some service that is being offered. Usually (but not
always), the application name and the s_User fields
together are unique system wide.
Type: std::string
Name: s_User
Description: The name of the user that was running the application that reserved this port. In the event that several users have run the same application on a single system, this identifies which user ran the application that requested this port.
CPortManagerException objects are thrown in most cases
the library encounters an exception.
The CPortManagerException is thrown to inform the
program of most errors dected by this API. For more information about
this exception, see: CPortManagerException(3).
Allocates a port to MyApplication
Example 1. Allocating a port with the port manager
…
CPortManager pm;
int port;
try {
port = pm.allocatePort("MyApplication");
ListenOnPort(port); // Not shown for brevity
}
catch (CPortManagerException& error) {
cerr << "Could not allocate a port: " << error << endl;
exit(-1);
}
…
Lists to cout the port allocations on the system: ahost.nscl.msuedu
Example 2. Listing the port allocatiosn on a system.
…
CPortManager pm("ahost.nscl.msu.edu");
vector<CPortManager::portInfo> info = pm.getPortUsage();
for(int i =0; i < info.size(); i++) {
cout << "Port " << info.s_Port
<< " allocated to " << info.s_Application
<< " run by " << info.s_User << endl;
}
…