Detailed Description
Defines and optionally creates a shared memory section.
Shared memory sections are used by DRAMA in the handling of bulk data transfers.
If Type is set to ShareType::Create, then this class's main constructor creates a temporary shared memory section of the size specified in some suitable form for the system it is running on. The caller has no control over the details of the shared memory section. In this case, the Name and Key arguments, and any preset value at the location specified by the Address argument are all ignored. A new section will be created and mapped.
VxWorks: The mapped section is just a section of memory, starting at a specified address. Type should be ShareType::Global. Name should be an empty string, and Key is ignored. If Create is specified, Address is ignored, and a suitably sized area of memory is allocated. If Create is passed as false, then Address should contain the address of the memory section in question. Under VxWorks, this is what is generated by ShareType::Default.
UNIX: The mapped section can be created as System V shared memory, in which case Type should be ShareType::SHMem , or as a file accessed through mmap(), in which case Type should be ShareType::MMap. If Type is ShareType::SHMem, Key specifies the identifier for the shared memory and Name should be an empty string. If Type is ShareType::MMap, Name should be the full name of the file, and Key is ignored. Address is ignored in both cases. On UNIX, one of these types will be what is provided by ShareType::Default.
- Revision
- 1.45
- Date
- 22-Feb-2016 14:09:57+11
- Id
- ACMM:Drama2/drama/bulkdata.hh,v 1.45 22-Feb-2016 14:09:57+11 tjf
#include "bulkdata.hh"
Public Member Functions | |
| BulkData () | |
| Default constructor. More... | |
| BulkData (std::weak_ptr< Task > theTask, long Size, ShareType type=ShareType::Create, bool Create=true, bool DeleteOnDestruct=true, void *Address=nullptr, const std::string &Name="", int Key=0) | |
| Define a bulk data shared memory segment of the specified type for use with DRAMA 2 methods which can send bulk data. More... | |
| BulkData (std::weak_ptr< Task > theTask, const DitsBulkReportInfoType &info) | |
| Define a bulk data shared memory segment based on a DitsBulkReportInfoType item. More... | |
| BulkData (const BulkData &source)=delete | |
| Copy constructor - deleted. More... | |
| BulkData (BulkData &&source) noexcept | |
| Move copy constructor. More... | |
| virtual | ~BulkData () |
| Destructor. More... | |
| template<typename T > | |
| T * | Data (unsigned long *nitems=nullptr) |
| Return a pointer to the actual data. More... | |
| DitsSharedMemInfoType & | GetDitsSharedMemInfo () |
| Return a reference to the DitsSharedMemInfoType object managed by this. More... | |
| BulkData & | operator= (const BulkData &rhs)=delete |
| Assignment operator - deleted. More... | |
| BulkData & | operator= (BulkData &&rhs) noexcept |
| Move assignment operator. More... | |
Protected Member Functions | |
| void * | RawDataAddr () const |
| Returns the raw address of the data. More... | |
| unsigned long | SizeBytes () const |
| Return the size of the data in bytes. More... | |
Constructor & Destructor Documentation
|
inline |
Default constructor.
Items created this way are only suitable as a target for Move Assignment and Move Copy operations. Attempts to access the memory item will throw an exception.
| drama::BulkData::BulkData | ( | std::weak_ptr< Task > | theTask, |
| long | Size, | ||
| ShareType | type = ShareType::Create, |
||
| bool | Create = true, |
||
| bool | DeleteOnDestruct = true, |
||
| void * | Address = nullptr, |
||
| const std::string & | Name = "", |
||
| int | Key = 0 |
||
| ) |
Define a bulk data shared memory segment of the specified type for use with DRAMA 2 methods which can send bulk data.
The parameters for this routine are used quite differently in the different systems for which DRAMA is implemented, and these system dependent details are described in more detail below.
- Parameters
-
theTask The DRAMA Task we are part of. This is passed by pointer, but BulkData is not taking ownership of the subject object, which must continue to exist until the BulkData object is destroyed. Size The size of the segment in bytes type The type of the shared memory item. See class description for more details. Create If true, the memory section does not actually exist and this routine is to create it. DeleteOnDestruct If set true, then the shared memory segment will be deleted when the BulkData item destructor is invoked. Address On systems with global address spaces, eg. VxWorks, the address of the memory is enough to specify it completely - together with its size. In any case, if the section is already mapped, this argument must specify the address at which it is mapped. If the section is created by this routine, it will ignored. Name Used to identify the mapped section on some machines. On UNIX, for example, if mapped files are used, this is the file name in question. If Name is not actually used on the current system it should be passed as an empty string. Key On some systems, this is an alternative way of specifying the mapped section. For example, if System V shared memory is used under UNIX, this is the identifier for that shared memory.
| drama::BulkData::BulkData | ( | std::weak_ptr< Task > | theTask, |
| const DitsBulkReportInfoType & | info | ||
| ) |
Define a bulk data shared memory segment based on a DitsBulkReportInfoType item.
This constructor is not normally invoked by user code, instead it is used by the BulkDataArg class implementation.
This constructor is used to create a drama::BulkData item from details that have been returned by DitsBulkArgInfo(). These are used with the DRAMA C interface to allow action code to access bulk data arguments. This class provides a C++ interfaces.
The memory is not released or deleted when this item is destroyed, through the task which sent the message containing the bulk data is told that the item has been released
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inlinevirtual |
Destructor.
Release access to the shared memory.
The shared memory segment will be deleted if the DeleteOnDestruct flag to the constructor was set true.
|
delete |
Copy constructor - deleted.
A Move constructor is available and deals with most cases of interest.
|
inlinenoexcept |
Move copy constructor.
Often optimized out using the "copy elision" rule.
Member Function Documentation
|
inline |
Return a pointer to the actual data.
Will throw an exception if the shared memory segment has not been constructed correctly (e.g. it was generated by the default constructor - which can only be used as a target of a move assignment or move-copy operation.)
- Template Parameters
-
T The type of the data item. This needs to be a POD type, if not, compile will fail with a static assertion.
- Parameters
-
nitems If non-null, the number of items which can fit in the shared memory is returned here.
References DramaTHROW.
|
inline |
Return a reference to the DitsSharedMemInfoType object managed by this.
Will throw an exception if the shared memory segment has not been constructed correctly (e.g. it was generated by the default constructor - which can only be used as a target of a move assignment or move-copy operation.)
References DramaTHROW.
Assignment operator - deleted.
A Move assignment operator is available and deals with most cases of interest.
Referenced by drama::BulkDataArg::operator=().
Move assignment operator.
Often optimized out using the "copy elision" rule.
|
inlineprotected |
Returns the raw address of the data.
|
inlineprotected |
Return the size of the data in bytes.
The documentation for this class was generated from the following file:
