The File System interface also defines concrete classes that derive from the specific abstract exceptions. The standard file system interface returns exceptions using these concrete classes. Other implementations of the file system can derive their own exception classes from the abstract ones provided.
These concrete classes are shown in the following table:
| Concrete class | Exception | |
| TStandardFileSystemAccessDenied | kNoAccess | |
| kNoWriteAccess | ||
| kOperationNotAllowed | ||
| TStandardFileSystemTypeMismatch | kNotAFile | |
| kNotADirectory | ||
| kNotAVolume | ||
| TStandardFileSystemPositionError | kNoDataBeyondThisPosition | |
| kNotEnoughDataBeyondThisPosition | ||
| kPositionOutOfRange | ||
| TStandardFileSystemRangeLockError | kNoReadAllowedInRange | |
| kNoWriteAllowedInRange | ||
| TStandardFileSystemPermissionsError | kAllowsNoAccessForOthers | |
| kAllowsNoWriteAccessForOthers | ||
| TFileSystemEntityAlreadyExists | kEntityAlreadyExists | |
| TStandardFileSystemEntityInUse | kEntityInUseByClient | |
| kEntityInUseByFileSystem | ||
| kDirectoryContentsInUse | ||
| TStandardFileSystemEntityNotAvailable | kEntityNotFound | |
| kVolumeNotFound | ||
| kVolumeOffLine | ||
| kFileSystemNotFound | ||
| TStandardFileSystemObjectInvalid | kInvalidEntity | |
| kInvalidIterator | ||
| TStandardFileSystemVolumeAccessError | kReadOnly | |
| kWriteProtected | ||
| kNotEnoughSpace | ||
| TStandardFileSystemVolumeMountError | kUnknownFileSystem | |
| TStandardFileSystemPathNameError | kPathIdenticalOnFactorRoot | |
| kTooMuchToTruncate | ||
| kPartialTruncateMismatch | ||
| kZeroLengthName | ||
| TStandardFileSystemPathSegmentDoesNotExistError | kNoVolumes | |
| kIntermediateDirectoryDoesNotExist | ||
| kFinalSegmentDoesNotExist | ||
| kIntermediateSegmentNotADirectory | ||
| TStandardFileSystemMappedFileError | kUnableToMapSpecifiedRange |
Because multiple file systems can run simultaneously and a user can move your program to another file system without your knowledge, you need to be able to handle exceptions that another implementation of file system might throw. If you only catch standard exceptions (such as TStandardFileSystemObjectInvalid) you risk missing an exception. If you make sure of always catching the exceptions polymorphically (for example, also catch TFileSystemObjectInvalid) you can protect your code further. However, if you want to process the enumerated identifier in any way, you do need to catch specific standard exceptions.
CAUTION 
File system exceptions are not the only type of exceptions that can be thrown out of this interface. In addition to any specific exceptions that your code catches, you should close your exception list with:
catch(...)
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