--- product: Chilkat product_version: 11.7.0 language: pascal language_label: Lazarus Pascal class: Gzip license: bundle deprecated: false reference_html: https://www.chilkatsoft.com/refdoc/pascal_GzipRef.html --- # Chilkat Gzip — Lazarus Pascal — v11.7.0 > Chilkat 11.7.0 · language=pascal · class=Gzip > Other versions: replace `11.7.0` in this URL. Other languages: `https://www.chilkatsoft.com/ai-docs/v/11.7.0//classes/Gzip.md`. > Language-wide rules (install, unlock, error model, strings/bytes): `https://www.chilkatsoft.com/ai-docs/v/11.7.0/pascal/guide.md`. ## Purpose **Compress, decompress, inspect, and convert GZIP data in files or memory.** `Chilkat.Gzip` provides GZIP compression and decompression for file-based and in-memory workflows. It can compress and uncompress files, strings, byte arrays, `BinData`, and encoded data such as Base64 or hex. It also supports `.tar.gz` extraction, gzip metadata such as original filename, timestamp, and comments, and inspection of GZIP header information without fully expanding the compressed data. **File compression** Compress files to `.gz`, uncompress `.gz` files, and write decompressed output directly to disk. **Memory-based data** Work with byte arrays and `Chilkat.BinData` for applications that need compression or decompression without temporary files. **String workflows** Compress and uncompress strings with explicit charset handling for text data that must round-trip correctly. **Encoded GZIP data** Handle GZIP data represented as Base64, hex, or other supported encoded forms when binary data must be carried as text. **GZIP metadata** Set or inspect metadata such as original filename, modified time, comments, and extra data stored in the GZIP header. **Tar-gzip and XFDL** Extract `.tar.gz` archives and decode XFDL content that uses gzip-related encodings. **Common pattern:** Use `Gzip` when the data is a single GZIP stream, a `.gz` file, or a `.tar.gz` archive. For ZIP archives, use `Chilkat.Zip`; for raw deflate or zlib-style compression, use `Chilkat.Compression`. For an extended overview, see [Gzip Class Overview](https://www.chilkatsoft.com/gzip_overview.asp). ## Object creation, unlocking and error handling **Create / Free** ```pascal uses Chilkat.Gzip; var obj: TGzip; begin obj := TGzip.Create; try if not obj.IsValid then raise Exception.Create('Failed to create a TGzip instance.'); // ... use obj ... finally obj.Free; end; end; ``` `constructor Create;` Allocates the underlying CkGzip object and returns a new TGzip instance. Simply adding **Chilkat.Gzip** to the unit's `uses` clause is enough to locate and bind to the Chilkat shared library (DLL / .so / .dylib) at runtime — no separate load step is required. Check `obj.IsValid` after calling `Create`; it is `False` if the underlying library could not be found/loaded or the object could not be allocated (for example, when unlicensed). `destructor Destroy; override;` Every TGzip created by calling `Create` should eventually be released by calling `.Free` (inherited from `TObject`). The destructor automatically disposes the underlying CkGzip handle. A native (unmanaged) memory leak occurs if the object is never freed. Call `Global.UnlockBundle` once at the start of the program, before using this or any other Chilkat class. Any string unlocks a fully functional 30-day trial; a purchased unlock code is used in production. See `guide.md` for the exact code in Lazarus Pascal. ## Members common to every Chilkat class Documented once per language in `common-members.md`; listed here so this page is self-contained. | Property | Signature | Access | Meaning | |---|---|---|---| | `DebugLogFilePath` | `property DebugLogFilePath: string read GetDebugLogFilePath write SetDebugLogFilePath;` | read/write | If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. | | `LastErrorHtml` | `property LastErrorHtml: string read GetLastErrorHtml;` | read-only | Provides HTML-formatted information about the last called method or property. | | `LastErrorText` | `property LastErrorText: string read GetLastErrorText;` | read-only | Provides plain text information about the last called method or property. | | `LastErrorXml` | `property LastErrorXml: string read GetLastErrorXml;` | read-only | Provides XML-formatted information about the last called method or property. | | `LastMethodSuccess` | `property LastMethodSuccess: Boolean read GetLastMethodSuccess write SetLastMethodSuccess;` | read/write | Indicates the success or failure of the most recent method call: `True` means success, `False` means failure. | | `VerboseLogging` | `property VerboseLogging: Boolean read GetVerboseLogging write SetVerboseLogging;` | read/write | If set to `True`, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. | | `Version` | `property Version: string read GetVersion;` | read-only | Version of the component/library, such as "10.1.0" | ## Member index | Member | Kind | Signature | |---|---|---| | `AbortCurrent` | property, read/write | `property AbortCurrent: Boolean read GetAbortCurrent write SetAbortCurrent;` | | `Comment` | property, read/write | `property Comment: string read GetComment write SetComment;` | | `CompressionLevel` | property, read/write | `property CompressionLevel: Integer read GetCompressionLevel write SetCompressionLevel;` | | `Filename` | property, read/write | `property Filename: string read GetFilename write SetFilename;` | | `HeartbeatMs` | property, read/write | `property HeartbeatMs: Integer read GetHeartbeatMs write SetHeartbeatMs;` | | `LastModStr` | property, read/write | `property LastModStr: string read GetLastModStr write SetLastModStr;` | | `UseCurrentDate` | property, read/write | `property UseCurrentDate: Boolean read GetUseCurrentDate write SetUseCurrentDate;` | | `CompressBd` | method | `// binDat is a TBinData object. function CompressBd(binDat: TChilkatBase): Boolean;` | | `CompressFile` | method | `function CompressFile(const srcPath: string;     const destPath: string): Boolean;` | | `CompressFile2` | method | `function CompressFile2(const srcPath: string;     const embeddedFilename: string;     const destPath: string): Boolean;` | | `CompressFileBd` | method | `// bd is a TBinData object. function CompressFileBd(const filePath: string;     bd: TChilkatBase): Boolean;` | | `CompressSb` | method | `// sb is a TStringBuilder object. // bd is a TBinData object. function CompressSb(sb: TChilkatBase;     const charset: string;     bd: TChilkatBase): Boolean;` | | `CompressStringENC` | method | `function CompressStringENC(const inStr: string;     const charset: string;     const encoding: string): string;` | | `CompressStringToFile` | method | `function CompressStringToFile(const inStr: string;     const destCharset: string;     const destPath: string): Boolean;` | | `GetGzipInfo` | method | `// json is a TJsonObject object. function GetGzipInfo(const filePath: string;     json: TChilkatBase): Boolean;` | | `GetGzipInfoBd` | method | `// bd is a TBinData object. // json is a TJsonObject object. function GetGzipInfoBd(bd: TChilkatBase;     json: TChilkatBase): Boolean;` | | `IsGzip` | method | `// bd is a TBinData object. function IsGzip(bd: TChilkatBase): Boolean;` | | `LoadTaskCaller` | method | `// task is a TTask object. function LoadTaskCaller(task: TChilkatBase): Boolean;` | | `SetDt` | method | `// dt is a TCkDateTime object. function SetDt(dt: TChilkatBase): Boolean;` | | `SetExtraData` | method | `function SetExtraData(const encodedData: string;     const encoding: string): Boolean;` | | `UncompressBd` | method | `// binDat is a TBinData object. function UncompressBd(binDat: TChilkatBase): Boolean;` | | `UncompressBdToFile` | method | `// bd is a TBinData object. function UncompressBdToFile(bd: TChilkatBase;     const filePath: string): Boolean;` | | `UncompressFile` | method | `function UncompressFile(const srcPath: string;     const destPath: string): Boolean;` | | `UncompressFileToString` | method | `function UncompressFileToString(const srcPath: string;     const charset: string): string;` | | `UncompressStringENC` | method | `function UncompressStringENC(const inStr: string;     const charset: string;     const encoding: string): string;` | | `UnTarGz` | method | `function UnTarGz(const gzPath: string;     const destDir: string;     bNoAbsolute: Boolean): Boolean;` | | `XfdlToXml` | method | `function XfdlToXml(const xfldData: string): string;` | ## Properties ### Gzip.AbortCurrent `Chilkat 11.7.0 · pascal · Gzip · AbortCurrent · property · read/write · since 9.5.0.58` ```pascal property AbortCurrent: Boolean read GetAbortCurrent write SetAbortCurrent; ``` Set this property to `True` to request that the currently running operation be aborted. This is useful for long-running operations such as large file compression or decompression. Methods that complete quickly are generally not affected. If no method is currently running, the property is automatically reset to `False` when the next method begins. After an abort occurs, it is also reset to `False`. Both synchronous and asynchronous operations can be aborted. For synchronous calls, another thread must set this property. ### Gzip.Comment `Chilkat 11.7.0 · pascal · Gzip · Comment · property · read/write` ```pascal property Comment: string read GetComment write SetComment; ``` An optional comment to embed in the Gzip file when a `Compress*` method is called. ### Gzip.CompressionLevel `Chilkat 11.7.0 · pascal · Gzip · CompressionLevel · property · read/write · since 9.5.0.50` ```pascal property CompressionLevel: Integer read GetCompressionLevel write SetCompressionLevel; ``` Controls the compression level used when creating Gzip data. The value can range from `0` to `9`. - `0` = no compression - `9` = maximum compression The default value is `6`, which is a typical balance between compression size and speed. Higher levels may take significantly more CPU time while producing only slightly smaller output, depending on the data. ### Gzip.Filename `Chilkat 11.7.0 · pascal · Gzip · Filename · property · read/write` ```pascal property Filename: string read GetFilename write SetFilename; ``` The filename to embed in the Gzip file when a `Compress*` method is called. Some Gzip extraction tools use this embedded filename as the default output filename. ### Gzip.HeartbeatMs `Chilkat 11.7.0 · pascal · Gzip · HeartbeatMs · property · read/write` ```pascal property HeartbeatMs: Integer read GetHeartbeatMs write SetHeartbeatMs; ``` **Full documentation for this property (same in every language):** [Event Callback Examples](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/event_callback_examples.md) Specifies the interval, in milliseconds, between `AbortCheck` event callbacks. These callbacks allow an application to cancel certain long-running operations before they finish. The default value is `0`, which means no `AbortCheck` callbacks are triggered. ### Gzip.LastModStr `Chilkat 11.7.0 · pascal · Gzip · LastModStr · property · read/write` ```pascal property LastModStr: string read GetLastModStr write SetLastModStr; ``` Specifies the last-modified date/time to embed in the Gzip file when a `Compress*` method is called. The value must be provided as an RFC 822 formatted date/time string. **Example:** ``` Sun, 12 Apr 2026 12:45:26 GMT ``` If this property is not set, the current system date/time is used automatically. ### Gzip.UseCurrentDate `Chilkat 11.7.0 · pascal · Gzip · UseCurrentDate · property · read/write` ```pascal property UseCurrentDate: Boolean read GetUseCurrentDate write SetUseCurrentDate; ``` Controls the last-modified date/time assigned to files created by `Uncompress*` methods. When set to `True`, the extracted file uses the current date/time instead of the date/time stored in the Gzip data. ## Methods ### Gzip.CompressBd `Chilkat 11.7.0 · pascal · Gzip · CompressBd · method · since 9.5.0.67` ```pascal // binDat is a TBinData object. function CompressBd(binDat: TChilkatBase): Boolean; ``` Compresses the contents of a `BinData` object in place, replacing the original data with Gzip-compressed data. Returns True for success, False for failure. ### Gzip.CompressFile `Chilkat 11.7.0 · pascal · Gzip · CompressFile · method` ```pascal function CompressFile(const srcPath: string;     const destPath: string): Boolean; ``` Compresses a file and writes the result as a Gzip file, typically with a `.gz` extension. Returns True for success, False for failure. ### Gzip.CompressFile2 `Chilkat 11.7.0 · pascal · Gzip · CompressFile2 · method` ```pascal function CompressFile2(const srcPath: string;     const embeddedFilename: string;     const destPath: string): Boolean; ``` Compresses a file and writes the result as a Gzip file, while allowing a different filename to be embedded inside the Gzip data. The `inFilename` parameter is the actual file on disk. The `srcPath` parameter is the filename stored in the Gzip header and may be used by extraction tools as the output filename. Returns True for success, False for failure. ### Gzip.CompressFileBd `Chilkat 11.7.0 · pascal · Gzip · CompressFileBd · method · since 11.0.0` ```pascal // bd is a TBinData object. function CompressFileBd(const filePath: string;     bd: TChilkatBase): Boolean; ``` Compresses a file and stores the resulting Gzip data in a `BinData` object. The compressed output is held in memory. The maximum compressed size is 4 GB. Returns True for success, False for failure. ### Gzip.CompressSb `Chilkat 11.7.0 · pascal · Gzip · CompressSb · method · since 11.0.0` ```pascal // sb is a TStringBuilder object. // bd is a TBinData object. function CompressSb(sb: TChilkatBase;     const charset: string;     bd: TChilkatBase): Boolean; ``` Compresses the text contained in a `StringBuilder` and writes the Gzip-compressed result to a `BinData` object. Before compression, the string is converted to bytes using the specified character set, such as `utf-8`, `iso-8859-1`, or `shift_JIS`. Returns True for success, False for failure. ### Gzip.CompressStringENC `Chilkat 11.7.0 · pascal · Gzip · CompressStringENC · method` ```pascal function CompressStringENC(const inStr: string;     const charset: string;     const encoding: string): string; ``` **Full documentation for this method (same in every language):** [Binary Encodings Supported by Chilkat](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/binary_encodings.md) Compresses a string and returns the Gzip-compressed data as an encoded string. The input string is first converted to bytes using the specified character set. The compressed binary data is then encoded using the requested encoding, such as `base64`, `hex`, `url`, `base32`, or quoted-printable. Returns True for success, False for failure. ### Gzip.CompressStringToFile `Chilkat 11.7.0 · pascal · Gzip · CompressStringToFile · method` ```pascal function CompressStringToFile(const inStr: string;     const destCharset: string;     const destPath: string): Boolean; ``` **Full documentation for this method (same in every language):** [Full List of Charset Names](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/charsets_supported_by_chilkat.md) Compresses a string and writes the resulting Gzip data to a file. The string is first converted to bytes using the character set specified by `destCharset`. Returns True for success, False for failure. ### Gzip.GetGzipInfo `Chilkat 11.7.0 · pascal · Gzip · GetGzipInfo · method · since 11.5.0` ```pascal // json is a TJsonObject object. function GetGzipInfo(const filePath: string;     json: TChilkatBase): Boolean; ``` Retrieves metadata stored in a Gzip file and returns the information in a `JsonObject`. The metadata is returned using the following JSON structure: ``` { "extraData": "AAECAw==", "filename": "example.txt", "comment": "This is the comment" } ``` - **filename** – the original filename embedded in the Gzip file (if present) - **comment** – an optional descriptive comment (if present) - **extraData** – optional additional binary data, returned as a Base64-encoded string Any of these fields may be omitted if they were not included when the Gzip file was created. Returns True for success, False for failure. ### Gzip.GetGzipInfoBd `Chilkat 11.7.0 · pascal · Gzip · GetGzipInfoBd · method · since 11.5.0` ```pascal // bd is a TBinData object. // json is a TJsonObject object. function GetGzipInfoBd(bd: TChilkatBase;     json: TChilkatBase): Boolean; ``` Retrieves metadata stored in Gzip data contained within a `BinData` object and returns the information in a `JsonObject`. The metadata is returned using the same JSON structure: ``` { "extraData": "AAECAw==", "filename": "example.txt", "comment": "This is the comment" } ``` - **filename** – the original filename embedded in the Gzip data (if present) - **comment** – an optional descriptive comment (if present) - **extraData** – optional additional binary data, returned as a Base64-encoded string Any of these fields may be omitted if they were not included when the Gzip data was created. Returns True for success, False for failure. ### Gzip.IsGzip `Chilkat 11.7.0 · pascal · Gzip · IsGzip · method · since 11.0.0` ```pascal // bd is a TBinData object. function IsGzip(bd: TChilkatBase): Boolean; ``` Checks whether the data contained in a `BinData` object is in Gzip format. Returns `True` if the data is Gzip-formatted, or `False` otherwise. ### Gzip.LoadTaskCaller `Chilkat 11.7.0 · pascal · Gzip · LoadTaskCaller · method · since 9.5.0.80` ```pascal // task is a TTask object. function LoadTaskCaller(task: TChilkatBase): Boolean; ``` Loads the caller of the task's async method. Returns True for success, False for failure. ### Gzip.SetDt `Chilkat 11.7.0 · pascal · Gzip · SetDt · method` ```pascal // dt is a TCkDateTime object. function SetDt(dt: TChilkatBase): Boolean; ``` Sets the last-modified date/time to embed in the Gzip file when a `Compress*` method is called. If no date/time is explicitly set, the current system date/time is used. Returns True for success, False for failure. ### Gzip.SetExtraData `Chilkat 11.7.0 · pascal · Gzip · SetExtraData · method · since 11.0.0` ```pascal function SetExtraData(const encodedData: string;     const encoding: string): Boolean; ``` **Full documentation for this method (same in every language):** [Binary Encodings Supported by Chilkat](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/binary_encodings.md) Sets optional extra binary data to include in the Gzip header when a `Compress*` method is called. The data is passed as an encoded string. Supported encodings include `base64`, `hex`, `ascii`, and many others. Returns True for success, False for failure. ### Gzip.UncompressBd `Chilkat 11.7.0 · pascal · Gzip · UncompressBd · method · since 9.5.0.67` ```pascal // binDat is a TBinData object. function UncompressBd(binDat: TChilkatBase): Boolean; ``` Decompresses Gzip data contained in a `BinData` object in place, replacing the compressed data with the uncompressed data. Returns True for success, False for failure. ### Gzip.UncompressBdToFile `Chilkat 11.7.0 · pascal · Gzip · UncompressBdToFile · method · since 11.0.0` ```pascal // bd is a TBinData object. function UncompressBdToFile(bd: TChilkatBase;     const filePath: string): Boolean; ``` Decompresses Gzip data stored in a `BinData` object and writes the result to a file. Returns True for success, False for failure. ### Gzip.UncompressFile `Chilkat 11.7.0 · pascal · Gzip · UncompressFile · method` ```pascal function UncompressFile(const srcPath: string;     const destPath: string): Boolean; ``` Decompresses a Gzip file and writes the result to the specified output path. The output filename is provided by the caller. The filename embedded in the Gzip data is not used. Returns True for success, False for failure. ### Gzip.UncompressFileToString `Chilkat 11.7.0 · pascal · Gzip · UncompressFileToString · method` ```pascal function UncompressFileToString(const srcPath: string;     const charset: string): string; ``` **Full documentation for this method (same in every language):** [List of Valid Charsets](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/charsets_supported_by_chilkat.md) Decompresses a Gzip file that contains text and returns the uncompressed text as a string. The `charset` parameter specifies the character encoding of the uncompressed text, such as `utf-8`, `iso-8859-1`, `windows-1252`, `shift_JIS`, `big5`, etc. Returns True for success, False for failure. ### Gzip.UncompressStringENC `Chilkat 11.7.0 · pascal · Gzip · UncompressStringENC · method` ```pascal function UncompressStringENC(const inStr: string;     const charset: string;     const encoding: string): string; ``` **Full documentation for this method (same in every language):** [Binary Encodings Supported by Chilkat](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/binary_encodings.md) Decompresses Gzip data provided as an encoded string and returns the uncompressed result as text. The input string is first decoded using the specified encoding, such as `base64`, `hex`, `url`, `base32`, quoted-printable, etc. The decoded Gzip data is then decompressed and converted to text using the specified character set. Returns True for success, False for failure. ### Gzip.UnTarGz `Chilkat 11.7.0 · pascal · Gzip · UnTarGz · method` ```pascal function UnTarGz(const gzPath: string;     const destDir: string;     bNoAbsolute: Boolean): Boolean; ``` Extracts a `.tar.gz` archive to a directory. The Gzip decompression and TAR extraction are performed in streaming mode. No temporary files are created, and memory usage remains small and constant. If `bNoAbsolute` is `True`, absolute paths in the TAR archive are not allowed. This helps protect against extracting files to unsafe locations, such as system directories. Returns True for success, False for failure. ### Gzip.XfdlToXml `Chilkat 11.7.0 · pascal · Gzip · XfdlToXml · method` ```pascal function XfdlToXml(const xfldData: string): string; ``` **Full documentation for this method (same in every language):** [More about XFDL](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/xfdl.md) Converts encoded and compressed XFDL data to a decompressed XML string. XFDL data is often stored in an ASCII-safe compressed form, such as `asci-gzip` or `asc-gzip`. Despite the name, this does not always mean the data is a standard `.gz` file. In some XFDL files, the compressed payload uses the raw deflate format rather than the full Gzip file format. Chilkat automatically detects the actual encoding and compression format used by the XFDL data. It decodes the ASCII/Base64 representation, determines whether the compressed data is Gzip or deflate, decompresses it correctly, and returns the resulting XML string. This allows applications to call `XfdlToXml` without needing to manually distinguish between XFDL variants such as Base64+Gzip and Base64+Deflate. Returns the decoded and decompressed XML string. **XFDL (Extensible Forms Description Language)** is an XML-based format used to define secure, interactive electronic forms—often including digital signatures and integrity protections—commonly used in government and enterprise applications. Returns True for success, False for failure. ## Events and callbacks Chilkat for Pascal supports three synchronous event callbacks: `OnAbortCheck`, `OnPercentDone`, and `OnProgressInfo`. Each is a property of the class; assign a method of one of your own objects (an *of object* handler) to receive the callbacks, or assign `nil` to unhook. The handler types are declared in the `Chilkat.Base` unit: ```pascal TChilkatAbortCheckEvent = function(Sender: TChilkatBase): Boolean of object; TChilkatPercentDoneEvent = function(Sender: TChilkatBase; PctDone: Integer): Boolean of object; TChilkatProgressInfoEvent = procedure(Sender: TChilkatBase; const Name, Value: string) of object; ``` All Chilkat methods are synchronous, so callbacks are invoked on the thread that called the method -- if the method was called from the main thread, it is safe to access UI elements from the handler. The `HeartbeatMs` property controls the frequency of `OnAbortCheck` callbacks (the default of 0 means no AbortCheck events fire). Returning `True` from an `OnAbortCheck` or `OnPercentDone` handler aborts the running method. ### Gzip.AbortCheck (event) `Chilkat 11.7.0 · pascal · Gzip · AbortCheck · event` ```pascal // TChilkatAbortCheckEvent = function(Sender: TChilkatBase): Boolean of object; property OnAbortCheck: TChilkatAbortCheckEvent; ``` Enables a method call to be aborted by triggering the AbortCheck event at intervals defined by the `HeartbeatMs` property. If HeartbeatMs is set to its default value of 0, no events will occur. For instance, set HeartbeatMs to 200 to trigger 5 AbortCheck events per second. **Event callback implementation:** ```pascal // A handler is a method of one of your own classes, e.g. a form: function TMyObject.GzipAbortCheck(Sender: TChilkatBase): Boolean; begin // Called every HeartbeatMs milliseconds while a method is running. // Return True to abort the method; return False to continue. Result := False; end; ``` **To add an event handler:** ```pascal gzip := TGzip.Create; gzip.HeartbeatMs := 250; // fire OnAbortCheck 4 times per second gzip.OnAbortCheck := MyObject.GzipAbortCheck; ``` ### Gzip.PercentDone (event) `Chilkat 11.7.0 · pascal · Gzip · PercentDone · event` ```pascal // TChilkatPercentDoneEvent = function(Sender: TChilkatBase; PctDone: Integer): Boolean of object; property OnPercentDone: TChilkatPercentDoneEvent; ``` This provides the percentage completion for any method involving network communications or time-consuming processing, assuming the progress can be measured as a percentage. This event is triggered only when it's possible and logical to express the operation's progress as a percentage. The `pctDone` argument will range from 1 to 100. For methods that finish quickly, the number of PercentDone callbacks may vary, but the final callback will have `pctDone` equal to 100. For longer operations, callbacks will not exceed one per percentage point (e.g., 1, 2, 3, ..., 98, 99, 100). The PercentDone callback also acts as an `AbortCheck` event. For fast methods where PercentDone fires, an AbortCheck event may not trigger since the PercentDone callback already provides an opportunity to abort. For longer operations, where time between PercentDone callbacks is extended, AbortCheck callbacks enable more responsive operation termination. To abort the operation, set the `abort` output argument to `True`. This will cause the method to terminate and return a failure status or corresponding failure value. **Event callback implementation:** ```pascal // A handler is a method of one of your own classes, e.g. a form: function TMyObject.GzipPercentDone(Sender: TChilkatBase; PctDone: Integer): Boolean; begin // PctDone ranges from 1 to 100. WriteLn('Percent done: ', PctDone); // Return True to abort the method; return False to continue. Result := False; end; ``` **To add an event handler:** ```pascal gzip := TGzip.Create; gzip.OnPercentDone := MyObject.GzipPercentDone; ``` ### Gzip.ProgressInfo (event) `Chilkat 11.7.0 · pascal · Gzip · ProgressInfo · event` ```pascal // TChilkatProgressInfoEvent = procedure(Sender: TChilkatBase; const Name, Value: string) of object; property OnProgressInfo: TChilkatProgressInfoEvent; ``` This event callback provides `tag name`/value pairs that detail what occurs during a method call. To discover existing tag names, create code to handle the event, emit the pairs, and review them. Most tag names are self-explanatory. Note: Some Chilkat methods don't fire any ProgressInfo events. **Event callback implementation:** ```pascal // A handler is a method of one of your own classes, e.g. a form: procedure TMyObject.GzipProgressInfo(Sender: TChilkatBase; const Name, Value: string); begin WriteLn(Name, ': ', Value); end; ``` **To add an event handler:** ```pascal gzip := TGzip.Create; gzip.OnProgressInfo := MyObject.GzipProgressInfo; ``` ## Related classes [`BinData`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/pascal/classes/BinData.md), [`CkDateTime`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/pascal/classes/CkDateTime.md), [`JsonObject`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/pascal/classes/JsonObject.md), [`StringBuilder`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/pascal/classes/StringBuilder.md)