FileAccess DataFlex Reference Documentation

FileAccess

Current Version: 9.5.0.98

API for reading and writing files, creating and deleting directories, deleting directory trees, splitting and re-joining large files, etc. This is a freeware class. The reason for its existence is that in some programming languages, file I/O API's are limited or difficult to understand/use. This API provides an identical FILE I/O API across all programming languages supported by Chilkat.

Object Creation

// (Dataflex programs use the 32-bit Chilkat ActiveX)
Handle hoFileAccess
Get Create(RefClass(cComCkFileAccess)) to hoFileAccess

Properties

CurrentDir
Function ComCurrentDir Returns String

The current working directory of the calling process.

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DebugLogFilePath
Function ComDebugLogFilePath Returns String
Procedure Set ComDebugLogFilePath String value

If set to a file path, causes each Chilkat method or property call to automatically append it's LastErrorText to the specified log file. The information is appended such that if a hang or crash occurs, it is possible to see the context in which the problem occurred, as well as a history of all Chilkat calls up to the point of the problem. The VerboseLogging property can be set to provide more detailed information.

This property is typically used for debugging the rare cases where a Chilkat method call hangs or generates an exception that halts program execution (i.e. crashes). A hang or crash should generally never happen. The typical causes of a hang are:

  1. a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
  2. the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
  3. there is an internal problem (bug) in the Chilkat code that causes the hang.

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EndOfFile
Function ComEndOfFile Returns Boolean

Returns True if the current open file is at the end-of-file.

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FileOpenError
Function ComFileOpenError Returns Integer

This property is set by the following methods: FileOpen, OpenForRead, OpenForWrite, OpenForReadWrite, and OpenForAppend. It provides an error code indicating the failure reason. Possible values are:

  1. Success (No error)
  2. Access denied.
  3. File not found.
  4. General (non-specific) open error.
  5. File aleady exists.
  6. Path refers to a directory and the access requested involves writing.
  7. Too many symbolic links were encountered in resolving path.
  8. The process already has the maximum number of files open.
  9. Pathname is too long.
  10. The system limit on the total number of open files has been reached.
  11. Pathname refers to a device special file and no corresponding device exists.
  12. Insufficient kernel memory was available.
  13. Pathname was to be created but the device containing pathname has no room for the new file.
  14. A component used as a directory in pathname is not, in fact, a directory.
  15. Pathname refers to a regular file, too large to be opened (this would be a limitation of the underlying operating system, not a limitation imposed by Chilkat).
  16. Pathname refers to a file on a read-only filesystem and write access was requested.

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FileOpenErrorMsg
Function ComFileOpenErrorMsg Returns String

The error message text associated with the FileOpenError code.

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LastBinaryResult
Function ComLastBinaryResult Returns Variant

The binary data returned by the last (binary data returning) method called. Only available if Chilkat.Global.KeepBinaryResult is set to True. This provides a means for obtaining large varbinary results in the SQL Server environment (where limitations exist in getting large amounts of data returned by method calls, but where temp tables can be used for binary properties).

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LastErrorHtml
Function ComLastErrorHtml Returns String

Provides information in HTML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorText
Function ComLastErrorText Returns String

Provides information in plain-text format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastErrorXml
Function ComLastErrorXml Returns String

Provides information in XML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

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LastMethodSuccess
Function ComLastMethodSuccess Returns Boolean
Procedure Set ComLastMethodSuccess Boolean value

Indicate whether the last method call succeeded or failed. A value of True indicates success, a value of False indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:

  • Any method that returns a string.
  • Any method returning a Chilkat object, binary bytes, or a date/time.
  • Any method returning a standard boolean status value where success = True and failure = False.
  • Any method returning an integer where failure is defined by a return value less than zero.

Note: Methods that do not fit the above requirements will always set this property equal to True. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

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LastStringResult
Function ComLastStringResult Returns String

The string return value of the last (string returning) method called. Only available if Chilkat.Global.KeepStringResult is set to True. This provides a means for obtaining large string results in the SQL Server environment (where limitations exist in getting long strings returned by method calls, but where temp tables can be used for string properties).

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LastStringResultLen
Function ComLastStringResultLen Returns Integer

The length, in characters, of the string contained in the LastStringResult property.

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LockFileOnOpen
Function ComLockFileOnOpen Returns Boolean
Procedure Set ComLockFileOnOpen Boolean value
Introduced in version 9.5.0.80

Note: This property only applies for applications running on Windows.

If True, then the following methods open files for exclusive-access: OpenForAppend, OpenForRead, OpenForReadWrite, OpenForWrite. When a file is opened for exclusive access, it is locked so that no other process may open the file. When the file is closed, the lock is released.

The default value of this property is False.

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VerboseLogging
Function ComVerboseLogging Returns Boolean
Procedure Set ComVerboseLogging Boolean value

If set to True, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is False. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

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Version
Function ComVersion Returns String

Version of the component/library, such as "9.5.0.94"

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Methods

AppendAnsi
Function ComAppendAnsi String text Returns Boolean

Appends a string using the ANSI character encoding to the currently open file.

Returns True for success, False for failure.

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AppendBd
Function ComAppendBd cComChilkatBinData bd Returns Boolean
Introduced in version 9.5.0.76

Appends the contents of bd to the currently open file.

Returns True for success, False for failure.

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AppendSb
Function ComAppendSb cComChilkatStringBuilder sb String charset Returns Boolean
Introduced in version 9.5.0.76

Appends the contents of sb using the character encoding (such as "utf-8") specified by charset to the currently open file.

Returns True for success, False for failure.

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AppendText
Function ComAppendText String str String charset Returns Boolean

Appends a string using the character encoding specified by str to the currently open file.

Returns True for success, False for failure.

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AppendUnicodeBOM
Function ComAppendUnicodeBOM Returns Boolean

Appends the 2-byte Unicode BOM (little endian) to the currently open file.

Returns True for success, False for failure.

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AppendUtf8BOM
Function ComAppendUtf8BOM Returns Boolean

Appends the 3-byte utf-8 BOM to the currently open file.

Returns True for success, False for failure.

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DirAutoCreate
Function ComDirAutoCreate String filePath Returns Boolean

Same as DirEnsureExists, except the argument is a file path (the last part of the path is a filename and not a directory). Creates all missing directories such that filePath may be created.

Returns True for success, False for failure.

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DirCreate
Function ComDirCreate String dirPath Returns Boolean

Creates a new directory specified by dirPath.

Returns True for success, False for failure.

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DirDelete
Function ComDirDelete String dirPath Returns Boolean

Deletes the directory specified by dirPath. It is only possible to delete a directory if it contains no files or subdirectories.

Returns True for success, False for failure.

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DirEnsureExists
Function ComDirEnsureExists String dirPath Returns Boolean

Creates all directories necessary such that the entire dirPath exists.

Returns True for success, False for failure.

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FileClose
Procedure ComFileClose

Closes the currently open file.

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FileContentsEqual
Function ComFileContentsEqual String filePath1 String filePath2 Returns Boolean

Compares the contents of two files and returns True if they are equal and otherwise returns False. The actual contents of the files are only compared if the sizes are equal. The files are not entirely loaded into memory. Instead, they are compared chunk by chunk. This allows for any size files to be compared, regardless of the memory capacity of the computer.

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FileCopy
Function ComFileCopy String existingFilepath String newFilepath Boolean failIfExists Returns Boolean

Copys existingFilepath to newFilepath. If failIfExists is True and newFilepath already exists, then an error is returned.

Returns True for success, False for failure.

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FileDelete
Function ComFileDelete String filePath Returns Boolean

Deletes the file specified by filePath.

Returns True for success, False for failure.

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FileExists
Function ComFileExists String filePath Returns Boolean

Returns True if filePath exists, otherwise returns False.

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FileExists3
Function ComFileExists3 String path Returns Integer
Introduced in version 9.5.0.45

Returns 1 if the file exists, 0 if the file does not exist, and -1 if unable to check because of directory permissions or some other error that prevents the ability to obtain the information.

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FileOpen
Function ComFileOpen String filePath Variant accessMode Variant shareMode Variant createDisposition Variant attributes Returns Boolean

This method should only be called on Windows operating systems. It's arguments are similar to the Windows Platform SDK function named CreateFile. For Linux, MAC OS X, and other operating system, use the OpenForRead, OpenForWrite, OpenForReadWrite, and OpenForAppend methods.

Opens a file for reading or writing. The arguments mirror the Windows CreateFile function:

Access Modes:
GENERIC_READ	(0x80000000)
GENERIC_WRITE (0x40000000)

Share Modes:
FILE_SHARE_READ(0x00000001)
FILE_SHARE_WRITE(0x00000002)

Create Dispositions
CREATE_NEW          1
CREATE_ALWAYS       2
OPEN_EXISTING       3
OPEN_ALWAYS         4
TRUNCATE_EXISTING   5

// Attributes:
FILE_ATTRIBUTE_READONLY         0x00000001
FILE_ATTRIBUTE_HIDDEN           0x00000002
FILE_ATTRIBUTE_SYSTEM           0x00000004
FILE_ATTRIBUTE_DIRECTORY        0x00000010
FILE_ATTRIBUTE_ARCHIVE          0x00000020
FILE_ATTRIBUTE_NORMAL           0x00000080
FILE_ATTRIBUTE_TEMPORARY	   0x00000100

Returns True for success, False for failure.

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FileRead
Function ComFileRead Integer maxNumBytes Returns Variant

Reads bytes from the currently open file. maxNumBytes specifies the maximum number of bytes to read. Returns an empty byte array on error.

Returns null on failure

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FileReadBd
Function ComFileReadBd Integer maxNumBytes cComChilkatBinData binData Returns Boolean
Introduced in version 9.5.0.64

Reads bytes from the currently open file. maxNumBytes specifies the maximum number of bytes to read. Appends the bytes to the binData.

Returns True for success, False for failure.

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FileRename
Function ComFileRename String existingFilepath String newFilepath Returns Boolean

Renames a file from existingFilepath to newFilepath.

Returns True for success, False for failure.

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FileSeek
Function ComFileSeek Integer offset Integer origin Returns Boolean

Sets the file pointer for the currently open file. The offset is an offset in bytes from the origin. The origin can be one of the following:

0 = Offset is from beginning of file.
1 = Offset is from current position of file pointer.
2 = Offset is from the end-of-file (offset may be negative).

Returns True for success, False for failure.

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FileSize
Function ComFileSize String filePath Returns Integer

Returns the size, in bytes, of a file. Returns -1 for failure.

Note: This method returns a signed 32-bit integer, which is not large enough to handle files greater than 2GB in size. To handle larger files, call FileSizeStr instead, or call FileSize64. The FileSize64 method was added in Chilkat v9.5.0.88.

Returns True for success, False for failure.

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FileSize64
Function ComFileSize64 String filePath
Introduced in version 9.5.0.88

Returns the size, in bytes, of a file. Returns -1 for failure.

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FileSizeStr
Function ComFileSizeStr String filePath Returns String
Introduced in version 9.5.0.80

Returns the size of the file in decimal string format.

Returns null on failure

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FileType
Function ComFileType String path Returns Integer
Introduced in version 9.5.0.77

Examines the file at path and returns one of the following values:

-1 = Unable to check because of directory permissions or some error preventing the ability to obtain the information.
0 = File does not exist.
1 = Regular file.
2 = Directory.
3 = Symbolic link.
4 = Windows Shortcut.
99 = Something else.

Additional file types may be added in the future as needed.

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FileWrite
Function ComFileWrite Variant data Returns Boolean

Writes bytes to the currently open file.

Returns True for success, False for failure.

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FileWriteBd
Function ComFileWriteBd cComChilkatBinData binData Integer offset Integer numBytes Returns Boolean
Introduced in version 9.5.0.64

Writes the contents of binData to the currently open file. To specify the entire contents of binData, set both offset and numBytes equal to 0. To write all remaining data starting at offset, then set numBytes equal to 0.

Returns True for success, False for failure.

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GenBlockId
Function ComGenBlockId Integer index Integer length String encoding Returns String
Introduced in version 9.5.0.58

This is purely a utility/convenience method -- initially created to help with block file uploads to Azure Blob storage. It generates a block ID string that is the decimal representation of the index in length chars, and then encoded according to encoding (which can be an encoding such as "base64", "hex", "ascii", etc.) For example, if index = 8, length = 12, and encoding = "base64", then the string "00000012" is returned base64 encoded.

Returns null on failure

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GetDirectoryName
Function ComGetDirectoryName String path Returns String
Introduced in version 9.5.0.64

Returns the directory information for the specified path string.

GetDirectoryName('C:\MyDir\MySubDir\myfile.ext') returns 'C:\MyDir\MySubDir\'
GetDirectoryName('C:\MyDir\MySubDir') returns 'C:\MyDir\'
GetDirectoryName('C:\MyDir\') returns 'C:\MyDir\'
GetDirectoryName('C:\MyDir') returns 'C:\'
GetDirectoryName('C:\') returns 'C:\'

Returns null on failure

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GetExtension
Function ComGetExtension String path Returns String
Introduced in version 9.5.0.64

Returns the extension of the specified path string.

GetExtension('C:\mydir.old\myfile.ext') returns '.ext'
GetExtension('C:\mydir.old\') returns ''

Returns null on failure

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GetFileName
Function ComGetFileName String path Returns String
Introduced in version 9.5.0.64

Returns the file name and extension of the specified path string.

GetFileName('C:\mydir\myfile.ext') returns 'myfile.ext'
GetFileName('C:\mydir\') returns ''

Returns null on failure

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GetFileNameWithoutExtension
Function ComGetFileNameWithoutExtension String path Returns String
Introduced in version 9.5.0.64

Returns the file name of the specified path string without the extension.

GetFileNameWithoutExtension('C:\mydir\myfile.ext') returns 'myfile'
GetFileNameWithoutExtension('C:\mydir\') returns ''

Returns null on failure

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GetFileTime
Function ComGetFileTime String path Integer which Returns cComCkDateTime
Introduced in version 9.5.0.71

Gets one of the following date/times for a file:

0: Last-modified
1: Last-access
2: Creation
The "path" argument indicates which time to return. The values can be 0, 1, or 2.

Note: Linux filesystems do not keep a file's creation date/time. In such a case, this method will return the last-modified time.

Returns null on failure

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GetLastModified
Function ComGetLastModified String path Returns cComCkDateTime
Introduced in version 9.5.0.66

Gets the last-modified date/time for a file. The accuracy of the last-modified data is to the number of seconds.

Returns null on failure

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GetNumBlocks
Function ComGetNumBlocks Integer blockSize Returns Integer
Introduced in version 9.5.0.58

Returns the number of blocks in the currently open file. The number of bytes per block is specified by blockSize. The number of blocks is the file size divided by the blockSize, plus 1 if the file size is not evenly divisible by blockSize. For example, if the currently open file is 60500 bytes, and if the blockSize is 1000 bytes, then this method returns a count of 61 blocks.

Returns -1 if no file is open. Return 0 if the file is completely empty (0 bytes).

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GetTempFilename
Function ComGetTempFilename String dirPath String prefix Returns String

Creates a temporary filepath of the form dirPath\prefix_xxxx.TMP Where "xxxx" are random alpha-numeric chars. The returned filepath is guaranteed to not already exist.

Returns null on failure

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OpenForAppend
Function ComOpenForAppend String filePath Returns Boolean

Opens a file for appending. If filePath did not already exists, it is created. When an existing file is opened with this method, the contents will not be overwritten and the file pointer is positioned at the end of the file.

If the open/create failed, then error information will be available in the FileOpenError and FileOpenErrorMsg properties.

Returns True for success, False for failure.

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OpenForRead
Function ComOpenForRead String filePath Returns Boolean

Opens a file for reading. The file may contain any type of data (binary or text) and it must already exist. If the open failed, then error information will be available in the FileOpenError and FileOpenErrorMsg properties.

Returns True for success, False for failure.

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OpenForReadWrite
Function ComOpenForReadWrite String filePath Returns Boolean

Opens a file for reading/writing. If filePath did not already exists, it is created. When an existing file is opened with this method, the contents will not be overwritten, but the file pointer is positioned at the beginning of the file.

If the open/create failed, then error information will be available in the FileOpenError and FileOpenErrorMsg properties.

Returns True for success, False for failure.

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OpenForWrite
Function ComOpenForWrite String filePath Returns Boolean

Opens a file for writing. If filePath did not already exists, it is created. When an existing file is opened with this method, the contents will be overwritten. (For example, calling OpenForWrite on an existing file and then immediately closing the file will result in an empty file.) If the open/create failed, then error information will be available in the FileOpenError and FileOpenErrorMsg properties.

Returns True for success, False for failure.

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ReadBinaryToEncoded
Function ComReadBinaryToEncoded String filePath String encoding Returns String

Reads the entire contents of a binary file and returns it as an encoded string (using an encoding such as Base64, Hex, etc.) The encoding may be one of the following strings: base64, hex, qp, or url.

Returns null on failure

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ReadBlock
Function ComReadBlock Integer blockIndex Integer blockSize Returns Variant
Introduced in version 9.5.0.58

Reads the Nth block of a file, where the size of each block is specified by blockSize. The first block is at blockIndex 0. If the block to be read is the last in the file and there is not enough data to fill an entire block, then the partial block is returned.

Returns null on failure

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ReadBlockBd
Function ComReadBlockBd Integer blockIndex Integer blockSize cComChilkatBinData bd Returns Boolean
Introduced in version 9.5.0.79

Reads the Nth block of a file, where the size of each block is specified by blockSize. The first block is at blockIndex 0. If the block to be read is the last in the file and there is not enough data to fill an entire block, then the partial block is returned. The file data is appended to the contents of bd.

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ReadEntireFile
Function ComReadEntireFile String filePath Returns Variant

Reads the entire contents of a binary file and returns the data.

Returns null on failure

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ReadEntireTextFile
Function ComReadEntireTextFile String filePath String charset Returns String

Reads the entire contents of a text file, interprets the bytes according to the character encoding specified by charset, and returns the text file as a string.

Returns null on failure

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ReadNextFragment
Function ComReadNextFragment Boolean startAtBeginning String beginMarker String endMarker String charset cComChilkatStringBuilder sb Returns Integer
Introduced in version 9.5.0.80

Scans the currently open file (opened by calling OpenForRead) for the next chunk of text delimited by beginMarker and endMarker. The matched text, including the beginMarker and endMarker are appended to sb. The bytes of the text file are interpreted according to charset. If startAtBeginning equals True, then scanning begins at the start of the file. Otherwise scanning begins starting at the byte following the last matched fragment.

The return value of this function is:
0: No match was found.
1: Found the next matching fragment and appended to sb.
-1: Error reading the file.

To support a common need for use with XML files, the beginMarker is "XML tag aware". If the beginMarker is a string such as "", then it will also match "

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ReassembleFile
Function ComReassembleFile String partsDirPath String partPrefix String partExtension String reassembledFilename Returns Boolean

Reassembles a file previously split by the SplitFile method.

Returns True for success, False for failure.

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ReplaceStrings
Function ComReplaceStrings String filePath String charset String existingString String replacementString Returns Integer

Replaces all occurrences of existingString with replacementString in a file. The character encoding, such as utf-8, ansi, etc. is specified by charset.

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SetCurrentDir
Function ComSetCurrentDir String dirPath Returns Boolean

Sets the current working directory for the calling process to dirPath.

Returns True for success, False for failure.

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SetFileTimes
Function ComSetFileTimes String filePath cComCkDateTime createTime cComCkDateTime lastAccessTime cComCkDateTime lastModTime Returns Boolean

Sets the create date/time, the last-access date/time, and the last-modified date/time for a file. For non-Windows filesystems where create times are not implemented, the createTime is ignored.

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SetLastModified
Function ComSetLastModified String filePath cComCkDateTime lastModified Returns Boolean

Sets the last-modified date/time for a file.

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SplitFile
Function ComSplitFile String fileToSplit String partPrefix String partExtension Integer partSize String destDir Returns Boolean

Splits a file into chunks. To reassemble a split file, see the ReassembleFile method. Please refer to the example below:

Returns True for success, False for failure.

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SymlinkCreate
Function ComSymlinkCreate String targetPath String linkPath Returns Boolean
Introduced in version 9.5.0.77

Creates a symbolic link.

Note: On Windows systems, this is not the same as creating a shortcut. A Windows symbolic link and a Windows shortcut are two different things. Shortcut files are common on Windows, but not symbolic links. Creating a symbolic link requires a special privilege, unless running as administrator. To be able to create symbolic links, your user account or group needs to be listed in secpol.msc → Security Settings → Local Policies → User Rights Assignment → Create symbolic links. However the special setting is not needed when running within the development environment, such as from Visual Studio.

Returns True for success, False for failure.

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SymlinkTarget
Function ComSymlinkTarget String linkPath Returns String
Introduced in version 9.5.0.77

Returns the full pathname of the file at the end of the linkPath. Also handles Windows shortcut files by returning the absolute path of the target.

Returns null on failure

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TreeDelete
Function ComTreeDelete String path Returns Boolean

Deletes an entire directory tree (all files and sub-directories).

Returns True for success, False for failure.

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Truncate
Function ComTruncate Returns Boolean
Introduced in version 9.5.0.80

Truncates the currently open file at the current file position.

Returns True for success, False for failure.

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WriteEntireFile
Function ComWriteEntireFile String filePath Variant fileData Returns Boolean

Opens/creates filePath, writes fileData, and closes the file.

Returns True for success, False for failure.

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WriteEntireTextFile
Function ComWriteEntireTextFile String filePath String textData String charset Boolean includedPreamble Returns Boolean

Opens filePath, writes textData using the character encoding specified by charset, and closes the file. If includedPreamble is True and the charset is Unicode or utf-8, then the BOM is included at the beginning of the file.

Returns True for success, False for failure.

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