HtmlToText Unicode C Reference Documentation

HtmlToText

Current Version: 11.5.0

Chilkat.HtmlToText

Convert HTML into readable plain text with control over links, wrapping, and encoding.

Chilkat.HtmlToText converts HTML content into readable plain text. It can decode HTML entities, wrap output at a configurable right margin, optionally include or suppress hyperlink URLs, convert HTML supplied as a string or StringBuilder, and read or write files using an explicit character encoding.

HTML to plain text

Convert HTML markup into readable text suitable for display, logging, indexing, email alternatives, or text-only output.

Entity decoding

Decode HTML entities so text such as named entities and numeric character references becomes normal readable output.

Line wrapping

Use RightMargin to wrap text at a chosen width, or set it to 0 when no right-margin wrapping is wanted.

Link handling

Suppress hyperlink URLs for cleaner text, or emit URLs when the output needs to preserve the destination of HTML links.

StringBuilder support

Convert HTML directly from a StringBuilder when working with larger or incrementally built HTML content.

File and charset helpers

Read HTML from files and write text output using a specified character encoding.

Common pattern: Provide the HTML as a string, file, or StringBuilder, choose whether to decode entities and include link URLs, set the desired right margin, then convert the result to plain text. Use HtmlToText when the goal is readable text, not structured XML or DOM-style parsing.

Create/Dispose

HCkHtmlToTextW instance = CkHtmlToTextW_Create();
// ...
CkHtmlToTextW_Dispose(instance);
HCkHtmlToTextW CkHtmlToTextW_Create(void);

Creates an instance of the HCkHtmlToTextW object and returns a handle ("void *" pointer). The handle is passed in the 1st argument for the functions listed on this page.

void CkHtmlToTextW_Dispose(HCkHtmlToTextW handle);

Objects created by calling CkHtmlToTextW_Create must be freed by calling this method. A memory leak occurs if a handle is not disposed by calling this function. Also, any handle returned by a Chilkat "C" function must also be freed by the application by calling the appropriate Dispose method, such as CkHtmlToTextW_Dispose.

Properties

DebugLogFilePath
void CkHtmlToTextW_getDebugLogFilePath(HCkHtmlToTextW cHandle, HCkString retval);
void CkHtmlToTextW_putDebugLogFilePath(HCkHtmlToTextW cHandle, const wchar_t *newVal);
const wchar_t *CkHtmlToTextW_debugLogFilePath(HCkHtmlToTextW cHandle);

If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.

Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.

Possible causes of hangs include:

  • A timeout property set to 0, indicating an infinite timeout.
  • A hang occurring within an event callback in the application code.
  • An internal bug in the Chilkat code causing the hang.

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DecodeHtmlEntities
BOOL CkHtmlToTextW_getDecodeHtmlEntities(HCkHtmlToTextW cHandle);
void CkHtmlToTextW_putDecodeHtmlEntities(HCkHtmlToTextW cHandle, BOOL newVal);

Controls whether HTML character references are decoded when converting HTML to plain text. The default value is TRUE.

Value Behavior
TRUE HTML entities and numeric character references are decoded to their corresponding characters. For example, & becomes &.
FALSE Character references are left encoded in the plain-text output.
Typical use: Leave this property set to TRUE when the goal is human-readable text. Set it to FALSE when the original entity notation itself must be preserved.

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LastErrorHtml
void CkHtmlToTextW_getLastErrorHtml(HCkHtmlToTextW cHandle, HCkString retval);
const wchar_t *CkHtmlToTextW_lastErrorHtml(HCkHtmlToTextW cHandle);

Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastErrorText
void CkHtmlToTextW_getLastErrorText(HCkHtmlToTextW cHandle, HCkString retval);
const wchar_t *CkHtmlToTextW_lastErrorText(HCkHtmlToTextW cHandle);

Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastErrorXml
void CkHtmlToTextW_getLastErrorXml(HCkHtmlToTextW cHandle, HCkString retval);
const wchar_t *CkHtmlToTextW_lastErrorXml(HCkHtmlToTextW cHandle);

Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastMethodSuccess
BOOL CkHtmlToTextW_getLastMethodSuccess(HCkHtmlToTextW cHandle);
void CkHtmlToTextW_putLastMethodSuccess(HCkHtmlToTextW cHandle, BOOL newVal);

Indicates the success or failure of the most recent method call: TRUE means success, FALSE means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.

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RightMargin
int CkHtmlToTextW_getRightMargin(HCkHtmlToTextW cHandle);
void CkHtmlToTextW_putRightMargin(HCkHtmlToTextW cHandle, int newVal);

Controls line wrapping in the generated plain text. The default value is 80. As a line approaches the configured margin, Chilkat attempts to wrap at a SPACE character. Set this property to 0 to disable right-margin wrapping.

Soft margin: The right margin is a preferred wrapping point, not a guaranteed maximum line length. A long sequence with no suitable SPACE character may extend beyond the configured margin.

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SuppressLinks
BOOL CkHtmlToTextW_getSuppressLinks(HCkHtmlToTextW cHandle);
void CkHtmlToTextW_putSuppressLinks(HCkHtmlToTextW cHandle, BOOL newVal);

Controls whether hyperlink destination URLs are included in the generated plain text. The default value is TRUE.

Value Behavior
TRUE The visible anchor text is retained, but hyperlink destination URLs are omitted.
FALSE Hyperlink URLs are included. By default, they are collected in a References: section at the end of the plain text.
For example, with SuppressLinks set to FALSE, an HTML link whose visible text is chilkat and whose URL is https://www.chilkatsoft.com/ produces the visible text and a numbered reference at the end of the output.
Related options: When link URLs are enabled, UncommonOptions can be used to suppress the trailing references list with NoReferencesList or emit URLs inline with EmitUrls.

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UncommonOptions
void CkHtmlToTextW_getUncommonOptions(HCkHtmlToTextW cHandle, HCkString retval);
void CkHtmlToTextW_putUncommonOptions(HCkHtmlToTextW cHandle, const wchar_t *newVal);
const wchar_t *CkHtmlToTextW_uncommonOptions(HCkHtmlToTextW cHandle);
Introduced in version 11.0.0

Specifies uncommon HTML-to-text conversion options as a comma-separated list of keywords. The default is the empty string, which is appropriate for normal use.

Keyword Effect
NoReferencesList Does not generate the hyperlink-reference list at the end of the plain-text output.
EmitUrls Emits hyperlink URLs inline in the plain-text output instead of relying on the default trailing reference list.
Interaction with SuppressLinks: These options control the presentation of hyperlink URLs when URL output is enabled. If SuppressLinks is TRUE, hyperlink URLs are suppressed.

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VerboseLogging
BOOL CkHtmlToTextW_getVerboseLogging(HCkHtmlToTextW cHandle);
void CkHtmlToTextW_putVerboseLogging(HCkHtmlToTextW cHandle, 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 CkHtmlToTextW_getVersion(HCkHtmlToTextW cHandle, HCkString retval);
const wchar_t *CkHtmlToTextW_version(HCkHtmlToTextW cHandle);

Version of the component/library, such as "10.1.0"

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Methods

ToText
BOOL CkHtmlToTextW_ToText(HCkHtmlToTextW cHandle, const wchar_t *html, const wchar_t *outStr);
const wchar_t *CkHtmlToTextW_toText(HCkHtmlToTextW cHandle, const wchar_t *html);

Converts the HTML in html to readable plain text and returns the result. The conversion honors DecodeHtmlEntities, RightMargin, SuppressLinks, and UncommonOptions. HTML markup is interpreted to produce readable text rather than simply being removed with a tag-stripping operation.

Plain-text conversion: The output is intended for reading, indexing, logging, email text alternatives, and similar text-oriented uses. It is not intended to preserve the original HTML markup or visual layout exactly.

Returns TRUE for success, FALSE for failure.

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ToTextSb
BOOL CkHtmlToTextW_ToTextSb(HCkHtmlToTextW cHandle, HCkStringBuilderW sb);
Introduced in version 9.5.0.97

Converts the HTML currently contained in sb to plain text in place. On success, the same StringBuilder contains the converted plain-text result. The conversion honors DecodeHtmlEntities, RightMargin, SuppressLinks, and UncommonOptions.

StringBuilder workflow: Use this method when the HTML is already held in a StringBuilder and you want the conversion result returned through that same object rather than as a separate string.

Returns TRUE for success, FALSE for failure.

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Deprecated

ReadFileToString
BOOL CkHtmlToTextW_ReadFileToString(HCkHtmlToTextW cHandle, const wchar_t *filename, const wchar_t *srcCharset, const wchar_t *outStr);
const wchar_t *CkHtmlToTextW_readFileToString(HCkHtmlToTextW cHandle, const wchar_t *filename, const wchar_t *srcCharset);
This method is deprecated.

Reads an entire text file and returns its contents as a string. The srcCharset argument specifies the character encoding used to decode the file bytes, such as utf-8 or iso-8859-1.

Convenience method: This method only reads and decodes the file. It does not perform HTML-to-text conversion. A typical workflow is to read the HTML with ReadFileToString and pass the returned string to ToText.
See the List of Charsets for supported charset names.

Returns TRUE for success, FALSE for failure.

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WriteStringToFile
BOOL CkHtmlToTextW_WriteStringToFile(HCkHtmlToTextW cHandle, const wchar_t *stringToWrite, const wchar_t *filename, const wchar_t *charset);
This method is deprecated.

Writes stringToWrite to filename using the character encoding specified by charset. The string is converted to that charset as it is written. Common values include utf-8 and iso-8859-1.

Convenience method: This method performs file output only; it does not convert HTML. To save converted text, first call ToText, then pass that result to WriteStringToFile.
See the List of Charsets for supported charset names.

Returns TRUE for success, FALSE for failure.

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