## class StructSet

> A set of structs to be received.

### Public Methods

  FDSet& | ExceptFDs () returns a reference to the set of file descriptors, that you're expecting to get into an exceptional condition.
  const FDSet& | ExceptFDs () const returns the set of file descriptors, that you're expecting to get into an exceptional condition.
  bool | FDsReady () const returns true if any file descriptor is ready.
  const FDSet& | ReadFDs () const returns the set of file descriptors, you want to read from.
  const FDSet& | ReadyExceptFDs () const returns the set of file descriptors, that have an exceptional condition pending.
  const FDSet& | ReadyReadFDs () const returns the set of file descriptors, that are ready to read from.
  const FDSet& | ReadyWriteFDs () const returns the set of file descriptors, that are ready to write to.
  StructId | Receive (Task &From = IgnoreTask) receives a message of one of the types in the set and returns the id of that message and the id of the sender in From.
  StructId | ReceiveFrom (Task From) receives a message of one of the types in the set, but only from the task From.
  StructId | ReceiveFrom (const TaskSet &FromSet, Task &From = IgnoreTask) receives a message of one of the types in the set, but only from one of the tasks given by FromSet, and returns the id of that message and the id of the sender in From.
  StructId | TimedReceive (unsigned long int &Time, Task &From = IgnoreTask) receives a message of one of the types in the set and returns the the id of the sender in From.
  StructId | TimedReceiveFrom (Task From, unsigned long int &Time) receives a message of one of the types in the set, but only from the task From.
  StructId | TimedReceiveFrom (const TaskSet &FromSet, unsigned long int &Time, Task &From = IgnoreTask) receives a message of one of the types in the set, but only from one of the tasks given by FromSet, and returns the id of the sender in From.
  FDSet& | WriteFDs () returns a reference to the set of file descriptors, you want to write to.
  const FDSet& | WriteFDs () const returns the set of file descriptors, you want to write to.
  int | count (StructId What) const returns 1, if an instance with the StructId` is in the set and 0 otherwise.
  int | count (const Struct &What) const returns 1, if What (not just any instance with the same StructId as What) is in the set and 0 otherwise.
  void | erase (StructId What) erases the potentially contained instance with the StructId What.
  void | erase (const Struct &What) erases the potentially contained instance with the same StructId as What.
  void | insert (Struct &What) inserts a reference to the instance What into the set.

### Public Members

  typedef std::set< int > | FDSet the type representing a set of file descriptors.

## Documentation

> A set of structs to be received.

> A StructSet is of course a set of Struct derivations. But in contrast to the classes TaskSet and HostSet it is not derived from the STL-class set. Yet some of the methods are available with the same name as in the STL. You can add a Struct to the StructSet and can remove one from there. If you want to receive messages of, let's say, three different types, then you simply add instances of all those three Struct-derivations to a StructSet and do a Receive*() (syntax and semantic are analogous to those in Struct.Receive*()). Then you get a return value with the id of the received message (as given with SetStructId()) or 0, in case no message has been received (e.g. if it is a timed receive). Now you find the received information in the previously added instance of the corresponding type. So a code-fragment looks like this:

>           StructA A; // derived from Pvm::Struct; Id = A_Id;
>           StructB B; // derived from Pvm::Struct; Id = B_Id;
>           Pvm::StructSet Awaited;
>           Awaited.insert (A);
>           Awaited.insert (B);
>           while (1)
>             {
>               Pvm::StructId Id = Awaited.ReceiveFrom (SendingTask);
>               if (Id == A_Id)
>               {
>                 cout << A.what_ever_data_is_in_A << endl;
>               }
>               else // now Id must be equal B_Id
>               {
>                 cout << B.what_ever_data_is_in_B << endl;
>               }
>             }

`void insert(Struct &What)`
  inserts a reference to the instance What into the set. There can inly be one instance of every type (determined by the corresponding StructId) inside such a set. So an instance overrides potentially contained ones of the same type.

`void erase(const Struct &What)`
  erases the potentially contained instance with the same StructId as What.

`void erase(StructId What)`
  erases the potentially contained instance with the StructId What.

`int count(const Struct &What) const`
  returns 1, if What (not just any instance with the same StructId as What) is in the set and 0 otherwise.

`int count(StructId What) const`
  returns 1, if an instance with the StructId` is in the set and 0 otherwise.

`StructId Receive(Task &From = IgnoreTask)`
  receives a message of one of the types in the set and returns the id of that message and the id of the sender in From. The parameter can be omitted, if you're not interested in who was sending. The message is unpacked into the instance that was added to set at. The call blocks until a message is received. If one of the file descriptor sets is not empty, the function returns immediatly 0, if the corresponding action on the file desriptor is possible. Subsequent calls to the Ready*FDs()-methods return the ready file descriptors. The input sets are not changed.

`StructId ReceiveFrom(const TaskSet &FromSet, Task &From = IgnoreTask)`
  receives a message of one of the types in the set, but only from one of the tasks given by FromSet, and returns the id of that message and the id of the sender in From. This parameter can be omitted. The message is unpacked into the instance that was added to set at.The call blocks until a message is received. If one of the file descriptor sets is not empty, the function returns immediatly 0, if the corresponding action on the file desriptor is possible. Subsequent calls to the Ready*FDs()-methods return the ready file descriptors. The input sets are not changed.

`StructId ReceiveFrom(Task From)`
  receives a message of one of the types in the set, but only from the task From. It returns the id of the message. The message is unpacked into the instance that was added to set at.The call blocks until a message is received. If one of the file descriptor sets is not empty, the function returns immediatly 0, if the corresponding action on the file desriptor is possible. Subsequent calls to the Ready*FDs()-methods return the ready file descriptors. The input sets are not changed.

`StructId TimedReceive(unsigned long int &Time, Task &From = IgnoreTask)`
  receives a message of one of the types in the set and returns the the id of the sender in From. This parameter can be omitted. The parameter Time specifies the maximal blocking time in microseconds. If after this time no message is received, than the function returns 0, otherwise it returns the id of the message and the remaining time in Time immediately after receiving the message. If received, the message is unpacked into the instance that was added to set at. If one of the file descriptor sets is not empty, the function returns immediatly 0, if the corresponding action on the file desriptor is possible. Subsequent calls to the Ready*FDs()-methods return the ready file descriptors. The input sets are not changed.

`StructId TimedReceiveFrom(const TaskSet &FromSet, unsigned long int &Time, Task &From = IgnoreTask)`
  receives a message of one of the types in the set, but only from one of the tasks given by FromSet, and returns the id of the sender in From. This parameter can be omitted. The parameter Time specifies the maximal blocking time in microseconds. If after this time no message is received, than the function returns 0, otherwise it returns the id of the message and the remaining time in Time immediately after receiving the message. If received, the message is unpacked into the instance that was added to set at. If one of the file descriptor sets is not empty, the function returns immediatly 0, if the corresponding action on the file desriptor is possible. Subsequent calls to the Ready*FDs()-methods return the ready file descriptors. The input sets are not changed.

`StructId TimedReceiveFrom(Task From, unsigned long int &Time)`
  receives a message of one of the types in the set, but only from the task From. The parameter Time specifies the maximal blocking time in microseconds. If after this time no message is received, than the function returns 0,otherwise it returns the id of the message and the remaining time in Time immediately after receiving the message. If received, the message is unpacked into the instance that was added to set at. If one of the file descriptor sets is not empty, the function returns immediatly 0, if the corresponding action on the file desriptor is possible. Subsequent calls to the Ready*FDs()-methods return the ready file descriptors. The input sets are not changed.

`typedef std::set< int > FDSet`
  the type representing a set of file descriptors.

`const FDSet& ReadFDs() const`
  returns the set of file descriptors, you want to read from.

`const FDSet& ReadyReadFDs() const`
  returns the set of file descriptors, that are ready to read from.

`FDSet& WriteFDs()`
  returns a reference to the set of file descriptors, you want to write to.

`const FDSet& WriteFDs() const`
  returns the set of file descriptors, you want to write to.

`const FDSet& ReadyWriteFDs() const`
  returns the set of file descriptors, that are ready to write to.

`FDSet& ExceptFDs()`
  returns a reference to the set of file descriptors, that you're expecting to get into an exceptional condition.

`const FDSet& ExceptFDs() const`
  returns the set of file descriptors, that you're expecting to get into an exceptional condition.

`const FDSet& ReadyExceptFDs() const`
  returns the set of file descriptors, that have an exceptional condition pending.

`bool FDsReady() const`
  returns true if any file descriptor is ready.

This class has no child classes.

Friends:
  class AccessPrivate

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