CkSpider C++ Reference Documentation

CkSpider

Current Version: 9.5.0.75

Chilkat Spider web crawler component.

Object Creation

// Local variable on the stack
CkSpider obj;

// Dynamically allocate/delete
CkSpider *pObj = new CkSpider();
// ...
delete pObj;

Properties

AbortCurrent
bool get_AbortCurrent(void);
void put_AbortCurrent(bool newVal);
Introduced in version 9.5.0.58

When set to true, causes the currently running method to abort. Methods that always finish quickly (i.e.have no length file operations or network communications) are not affected. If no method is running, then this property is automatically reset to false when the next method is called. When the abort occurs, this property is reset to false. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)

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AvoidHttps
bool get_AvoidHttps(void);
void put_AvoidHttps(bool newVal);

If set the 1 (true) the spider will avoid all HTTPS URLs. The default is 0 (false).

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CacheDir
void get_CacheDir(CkString &str);
const char *cacheDir(void);
void put_CacheDir(const char *ansiOrUtf8Str);

Specifies a cache directory to use for spidering. If either of the FetchFromCache or UpdateCache properties are true, this is the location of the cache to be used. Note: the Internet Explorer, Netscape, and FireFox caches are completely separate from the Chilkat Spider cache directory. You should specify a new and empty directory.

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ChopAtQuery
bool get_ChopAtQuery(void);
void put_ChopAtQuery(bool newVal);

If equal to 1 (true), then the query portion of all URLs are automatically removed when adding to the unspidered list. The default value is 0 (false).

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ConnectTimeout
int get_ConnectTimeout(void);
void put_ConnectTimeout(int newVal);

The maximum number of seconds to wait while connecting to an HTTP server.

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DebugLogFilePath
void get_DebugLogFilePath(CkString &str);
const char *debugLogFilePath(void);
void put_DebugLogFilePath(const char *ansiOrUtf8Str);

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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Domain
void get_Domain(CkString &str);
const char *domain(void);

The domain name that is being spidered. This is the domain previously set in the Initialize method.

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FetchFromCache
bool get_FetchFromCache(void);
void put_FetchFromCache(bool newVal);

If equal to 1 (true) then pages are fetched from cache when possible. If 0, the cache is ignored. The default value is 1. Regardless, if no CacheDir is set then the cache is not used.

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HeartbeatMs
int get_HeartbeatMs(void);
void put_HeartbeatMs(int newVal);

The number of milliseconds between each AbortCheck event callback. The AbortCheck callback allows an application to abort any method call prior to completion. If HeartbeatMs is 0 (the default), no AbortCheck event callbacks will fire.

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LastErrorHtml
void get_LastErrorHtml(CkString &str);
const char *lastErrorHtml(void);

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
void get_LastErrorText(CkString &str);
const char *lastErrorText(void);

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
void get_LastErrorXml(CkString &str);
const char *lastErrorXml(void);

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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LastFromCache
bool get_LastFromCache(void);

Equal to 1 if the last page spidered was fetched from the cache. Otherwise equal to 0.

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LastHtml
void get_LastHtml(CkString &str);
const char *lastHtml(void);

The HTML text of the last paged fetched by the spider.

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LastHtmlDescription
void get_LastHtmlDescription(CkString &str);
const char *lastHtmlDescription(void);

The HTML META description from the last page fetched by the spider.

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LastHtmlKeywords
void get_LastHtmlKeywords(CkString &str);
const char *lastHtmlKeywords(void);

The HTML META keywords from the last page fetched by the spider.

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LastHtmlTitle
void get_LastHtmlTitle(CkString &str);
const char *lastHtmlTitle(void);

The HTML title from the last page fetched by the spider.

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LastMethodSuccess
bool get_LastMethodSuccess(void);
void put_LastMethodSuccess(bool newVal);
Introduced in version 9.5.0.52

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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LastModDateStr
void get_LastModDateStr(CkString &str);
const char *lastModDateStr(void);

The last modification date/time from the last page fetched by the spider.

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LastUrl
void get_LastUrl(CkString &str);
const char *lastUrl(void);

The URL of the last page spidered.

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MaxResponseSize
int get_MaxResponseSize(void);
void put_MaxResponseSize(int newVal);

The maximum HTTP response size allowed. The spider will automatically fail any pages larger than this size. The default value is 250,000 bytes.

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MaxUrlLen
int get_MaxUrlLen(void);
void put_MaxUrlLen(int newVal);

The maximum URL length allowed. URLs longer than this are not added to the unspidered list. The default value is 200.

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NumAvoidPatterns
int get_NumAvoidPatterns(void);

The number of avoid patterns previously set by calling AddAvoidPattern.

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NumFailed
int get_NumFailed(void);

The number of URLs in the component's failed URL list.

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NumOutboundLinks
int get_NumOutboundLinks(void);

The number of URLs in the component's outbound links URL list.

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NumSpidered
int get_NumSpidered(void);

The number of URLs in the component's already-spidered URL list.

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NumUnspidered
int get_NumUnspidered(void);

The number of URLs in the component's unspidered URL list.

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PreferIpv6
bool get_PreferIpv6(void);
void put_PreferIpv6(bool newVal);

If true, then use IPv6 over IPv4 when both are supported for a particular domain. The default value of this property is false, which will choose IPv4 over IPv6.

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ProxyDomain
void get_ProxyDomain(CkString &str);
const char *proxyDomain(void);
void put_ProxyDomain(const char *ansiOrUtf8Str);

The domain name of a proxy host if an HTTP proxy is used.

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ProxyLogin
void get_ProxyLogin(CkString &str);
const char *proxyLogin(void);
void put_ProxyLogin(const char *ansiOrUtf8Str);

If an HTTP proxy is used and it requires authentication, this property specifies the HTTP proxy login.

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ProxyPassword
void get_ProxyPassword(CkString &str);
const char *proxyPassword(void);
void put_ProxyPassword(const char *ansiOrUtf8Str);

If an HTTP proxy is used and it requires authentication, this property specifies the HTTP proxy password.

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ProxyPort
int get_ProxyPort(void);
void put_ProxyPort(int newVal);

The port number of a proxy server if an HTTP proxy is used.

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ReadTimeout
int get_ReadTimeout(void);
void put_ReadTimeout(int newVal);

The maximum number of seconds to wait when reading from an HTTP server.

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UpdateCache
bool get_UpdateCache(void);
void put_UpdateCache(bool newVal);

If equal to 1 (true) then pages saved to the cache. If 0, the cache is ignored. The default value is 1. Regardless, if no CacheDir is set then the cache is not used.

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UserAgent
void get_UserAgent(CkString &str);
const char *userAgent(void);
void put_UserAgent(const char *ansiOrUtf8Str);

The value of the HTTP user-agent header field to be sent with HTTP requests. The default value is "Chilkat/1.0.0 (+http://www.chilkatsoft.com/ChilkatHttpUA.asp)"

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Utf8
bool get_Utf8(void);
void put_Utf8(bool newVal);

When set to true, all "const char *" arguments are interpreted as utf-8 strings. If set to false (the default), then "const char *" arguments are interpreted as ANSI strings. Also, when set to true, and Chilkat method returning a "const char *" is returning the utf-8 representation. If set to false, all "const char *" return values are ANSI strings.

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VerboseLogging
bool get_VerboseLogging(void);
void put_VerboseLogging(bool newVal);

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
void get_Version(CkString &str);
const char *version(void);

Version of the component/library, such as "9.5.0.63"

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WindDownCount
int get_WindDownCount(void);
void put_WindDownCount(int newVal);

The "wind-down" phase begins when this number of URLs has been spidered. When in the wind-down phase, no new URLs are added to the unspidered list. The default value is 0 which means that there is NO wind-down phase.

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Methods

AddAvoidOutboundLinkPattern
void AddAvoidOutboundLinkPattern(const char *pattern);

Adds a wildcarded pattern to prevent collecting matching outbound link URLs. For example, if "*google*" is added, then any outbound links containing the word "google" will be ignored. The "*" character matches zero or more of any character.

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AddAvoidPattern
void AddAvoidPattern(const char *pattern);

Adds a wildcarded pattern to prevent spidering matching URLs. For example, if "*register*" is added, then any url containing the word "register" is not spidered. The "*" character matches zero or more of any character.

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AddMustMatchPattern
void AddMustMatchPattern(const char *pattern);

Adds a wildcarded pattern to limit spidering to only URLs that match the pattern. For example, if "*/products/*" is added, then only URLs containing "/products/" are spidered. This is helpful for only spidering a portion of a website. The "*" character matches zero or more of any character.

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AddUnspidered
void AddUnspidered(const char *url);

To begin spidering you must call this method one or more times to provide starting points. It adds a single URL to the component's internal queue of URLs to be spidered.

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CanonicalizeUrl
bool CanonicalizeUrl(const char *url, CkString &outStr);
const char *canonicalizeUrl(const char *url);

Canonicalizes a URL by doing the following:

  • Drops username/password if present.
  • Drops fragment if present.
  • Converts domain to lowercase.
  • Removes port 80 or 443
  • Remove default.asp, index.html, index.htm, default.html, index.htm, default.htm, index.php, index.asp, default.php, .cfm, .aspx, ,php3, .pl, .cgi, .txt, .shtml, .phtml
  • Remove www. from the domain if present.

Returns true for success, false for failure.

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ClearFailedUrls
void ClearFailedUrls(void);

Clears the component's internal list of URLs that could not be downloaded.

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ClearOutboundLinks
void ClearOutboundLinks(void);

Clears the component's internal list of outbound URLs that will automatically accumulate while spidering.

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ClearSpideredUrls
void ClearSpideredUrls(void);

Clears the component's internal list of already-spidered URLs that will automatically accumulate while spidering.

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CrawlNext
bool CrawlNext(void);

Crawls the next URL in the internal list of unspidered URLs. The URL is moved from the unspidered list to the spidered list. Any new links within the same domain and not yet spidered are added to the unspidered list. (providing that they do not match "avoid" patterns, etc.) Any new outbound links are added to the outbound URL list. If successful, the HTML of the downloaded page is available in the LastHtml property. If there are no more URLs left unspidered, the method returns false. Information about the URL crawled is available in the properties LastUrl, LastFromCache, and LastModDate.

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CrawlNextAsync (1)
CkTask *CrawlNextAsync(void);

Creates an asynchronous task to call the CrawlNext method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Note: The application is responsible for deleting (via the C++ delete operator) the object returned by this method.

Returns NULL on failure

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FetchRobotsText
bool FetchRobotsText(CkString &outStr);
const char *fetchRobotsText(void);

Returns the contents of the robots.txt file from the domain being crawled. This spider component will not crawl URLs excluded by robots.txt. If you believe the spider is not behaving correctly, please notify us at support@chilkatsoft.com and provide information detailing a case that allows us to reproduce the problem.

Returns true for success, false for failure.

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FetchRobotsTextAsync (1)
CkTask *FetchRobotsTextAsync(void);

Creates an asynchronous task to call the FetchRobotsText method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Note: The application is responsible for deleting (via the C++ delete operator) the object returned by this method.

Returns NULL on failure

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GetAvoidPattern
bool GetAvoidPattern(int index, CkString &outStr);
const char *getAvoidPattern(int index);

Returns the Nth avoid pattern previously added by calling AddAvoidPattern. Indexing begins at 0.

Returns true for success, false for failure.

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GetBaseDomain
bool GetBaseDomain(const char *domain, CkString &outStr);
const char *getBaseDomain(const char *domain);

To be documented soon.

Returns true for success, false for failure.

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GetFailedUrl
bool GetFailedUrl(int index, CkString &outStr);
const char *getFailedUrl(int index);

Returns the Nth URL in the failed URL list. Indexing begins at 0.

Returns true for success, false for failure.

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GetOutboundLink
bool GetOutboundLink(int index, CkString &outStr);
const char *getOutboundLink(int index);

Returns the Nth URL in the outbound link URL list. Indexing begins at 0.

Returns true for success, false for failure.

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GetSpideredUrl
bool GetSpideredUrl(int index, CkString &outStr);
const char *getSpideredUrl(int index);

Returns the Nth URL in the already-spidered URL list. Indexing begins at 0.

Returns true for success, false for failure.

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GetUnspideredUrl
bool GetUnspideredUrl(int index, CkString &outStr);
const char *getUnspideredUrl(int index);

Returns the Nth URL in the unspidered URL list. Indexing begins at 0.

Returns true for success, false for failure.

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GetUrlDomain
bool GetUrlDomain(const char *url, CkString &outStr);
const char *getUrlDomain(const char *url);

Returns the domain name part of a URL. For example, if the URL is "http://www.chilkatsoft.com/test.asp", then "www.chilkatsoft.com" is returned.

Returns true for success, false for failure.

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Initialize
void Initialize(const char *domain);

Initializes the component to begin spidering a domain. Calling Initialize clears any patterns added via the AddAvoidOutboundLinkPattern, AddAvoidPattern, and AddMustMatchPattern methods. The domain name passed to this method is what is returned by the Domain property. The spider only crawls URLs within the same domain.

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RecrawlLast
bool RecrawlLast(void);

Re-crawls the last URL spidered. This helpful when cookies set in a previous page load cause the page to be loaded differently the next time.

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RecrawlLastAsync (1)
CkTask *RecrawlLastAsync(void);

Creates an asynchronous task to call the RecrawlLast method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Note: The application is responsible for deleting (via the C++ delete operator) the object returned by this method.

Returns NULL on failure

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SaveLastError
bool SaveLastError(const char *path);

Saves the last-error information (the contents of LastErrorXml) to an XML formatted file.

Returns true for success, false for failure.

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SkipUnspidered
void SkipUnspidered(int index);

Moves a URL from the unspidered list to the spidered list. This allows an application to skip a specific URL.

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SleepMs
void SleepMs(int numMilliseconds);

Suspends the execution of the current thread until the time-out interval elapses.

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Events

To implement an event callback, your application would define and implement a class that inherits from CkBaseProgress. Your application can implement methods to override some or all of the default/empty method implementations of the CkBaseProgress base class.

For example:

  CkSpider spider;

  MySpiderProgress callbackObj;

  spider.put_EventCallbackObject(&callbackObj);

MySpiderProgress example:

#include "CkBaseProgress.h"

class MySpiderProgress : public CkBaseProgress {

  public:
    MySpiderProgress();
    virtual ~MySpiderProgress();

    void AbortCheck(bool  *abort);

    void BinaryData(const void *data, unsigned int length);

    void PercentDone(int pctDone, bool  *abort);

    void ProgressInfo(const char *name, const char *value);

    void TaskCompleted(CkTask &task);

    void TextData(const char *data);

};
AbortCheck
void AbortCheck(bool *abort);

Provides the opportunity for a method call to be aborted. The AbortCheck event is fired periodically based on the value of the HeartbeatMs property. If HeartbeatMs is 0, then no AbortCheck events will fire. As an example, to fire 5 AbortCheck events per second, set the HeartbeatMs property equal to 200.

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PercentDone
void PercentDone(int pctDone, bool *abort);

Provides the percentage completed for any method that involves network communications or time-consuming processing (assuming it is a method where a percentage completion can be measured). This event is only fired when it is possible to know a percentage completion, and when it makes sense to express the operation as a percentage completed. The pctDone argument will have a value from 1 to 100. For operations (Chilkat method calls) that complete very quickly, the number of PercentDone callbacks will vary, but the final callback should have a value of 100. For long running operations, no more than one callback per percentage point will occur (for example: 1, 2, 3, ... 98, 99, 100).

The PercentDone callback counts as an AbortCheck event. For method calls that complete quickly such that PercentDone events fire, it may be that AbortCheck events don't fire because the opportunity to abort is already provided in the PercentDone callback. For time consuming operations, where the amount of time between PercentDone callbacks are long, AbortCheck callbacks may be used to allow for the operation to be aborted in a more responsive manner.

The abort output argument provides a means for aborting the operation. Setting it to true will cause the method to abort and return a failed status (or whatever return value indicates failure).

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ProgressInfo
void ProgressInfo(const char *name, const char *value);

A general name/value event that provides information about what is happening during a method call. To find out what information is available, write code to handle this event and log the name/value pairs. Most are self-explanatory.

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TaskCompleted
void TaskCompleted(CkTask &task);

Called in the background thread when an asynchronous task completes.

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