A helper class to work with the device specific non-volatile memory(if available).
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| UserDataEntry | createEntry (void) |
| | Creates and returns a new entry to store user specific data.
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| void | deleteEntry (UserDataEntry &userDataEntry) |
| | Deletes an entry of user specific data.
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| int | getFreeMemory (void) const |
| | Returns the number of bytes of user accessible, non-volatile memory that is still available.
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| UserDataEntry | getUserDataEntry (int nr) const |
| | Returns An object to work with an existing entry of user specific data.
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| bool | isAvailable (void) const |
| | This function should be called to check if this device offers non-volatile memory that can be accessed by the user.
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| void | validUserDataEntryIndexes (std::vector< int > &sequence) const |
| | Fills an array with all currently valid user data entry indexes.
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| void | writeToHardware (void) const |
| | Writes the current set of user data into the devices non-volatile memory.
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A helper class to work with the device specific non-volatile memory(if available).
A device might have a certain amount of non-volatile memory which can be accessed and modified by the user. This data can e.g. be used to store certain parameters or custom data permanently into the device. Thus this property e.g. can be used to store configuration data in the device before shipping it to the end user.
In theory the number of entries that can be stored in the device is not limited. However no device will provide an unlimited amount of memory.
Writing data to any property of a mvIMPACT::acquire::UserDataEntry as well as creating a new entry by calling mvIMPACT::acquire::UserData::createEntry or deleting an entry with the function mvIMPACT::acquire::UserData::deleteEntry will NOT automatically result in the complete data to be updated in the device specific memory. As writing to the device memory takes a long (in terms of ms) time depending on the device architecture the modifications will only become permanent when calling mvIMPACT::acquire::UserData::writeToHardware.
If data at the end of the list of entries doesn't fit in the memory it will be discarded and therefore will not be visible the next time the device is enumerated/accessed after the running process has terminated or the device has been disconnected.
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- Entries that contain no data will not be stored in hardware. If e.g. 5 user data entries have been created, but only entry 0, 1, 2 and 4 contain data the write operation will pack the data in a way that when the user data is read from the device again (when the driver for that device is loaded the next time) the list of entries will contain elements at position 0, 1, 2 and 3 but NOT a index number 4. Deleting an entry from the middle of the list of user data however will NOT move all remaining entries one step towards the front of the list. Therefore during one session the entry indexes will NOT change. They can either become invalid (when the corresponding entry has been deleted), can get valid (newly created entries will always appear at the next free entry, thus deleting and entry and creating a new directly afterwards will create that entry at exactly the same index) or new entries can appear (when a new entry has been created and no free list position in the middle of the list of entries has been available).
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The device must be closed in order to write the user data. Check the property mvIMPACT::acquire::Device::HWUpdateResult afterwards in order to make sure the data transfer was successful.
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If a device does not offer user accessible data mvIMPACT::acquire::UserDataEntry objects will still be returned by certain functions. To check if this feature is available call mvIMPACT::acquire::UserData::isAvailable.
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If the user accessible data currently can't be modified an exception of type mvIMPACT::acquire::ENoWriteRights will be thrown.
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Instances of this class cannot be constructed directly. To get access the function mvIMPACT::acquire::Device::getUserData. must be used.
An integer property (read-only) containing the number of bytes of user accessible, non-volatile memory currently consumed by user data.
This doesn't indicate that all the data has already been stored in the non-volatile memory, but is the number of bytes needed to store the current user data permanently. No check for overflows will be performed. If the user defined data exceeds the size of the available memory, this data will be lost when disconnecting or switching of the supply voltage for this device.
To write data permanently into the device call the function mvIMPACT::acquire::UserData::writeToHardware But even after calling this function data that exceeds the available memory will be lost when the device looses supply voltage and/or the process terminates.
