Configure Languages > C/C++ > IntelliSense options

This article describes how to modify IntelliSense settings for C and C++. You can access the settings by selecting Tools > Options from the Visual Studio menu bar and expanding the All Settings > Languages > C/C++ > IntelliSense section.

These options let you define the IntelliSense behavior for C and C++. Configure tooltips, browsing and navigation, references, refactoring, diagnostic logging, nonproject files, and more. For more information, see Visual C++ IntelliSense features.

General options

The following options are available in the C/C++ > IntelliSense section.

• Enable IntelliSense: When selected (default), IntelliSense features are available to support C and C++ programming. This option must be enabled to configure the other settings in this section.

  If you clear this option, all IntelliSense features are disabled and no IntelliSense features work (QuickInfo, Member List, Auto Complete, Param Help). Semantic colorization and reference highlighting are also disabled. This option doesn't disable browsing features that rely solely on the database (including the Navigation Bar, ClassView, and Property window).

• Use 64-bit IntelliSense engine: When selected, Visual Studio runs the 64-bit IntelliSense engine rather than the 32-bit engine, which is helpful for large projects and projects that include large SDKs. By default, this option isn't selected.

• Automatically update IntelliSense as you type: When selected (default), IntelliSense continuously parses and analyzes your code in real-time as you type. If you clear this option, IntelliSense only updates when you explicitly request it. An explicit request might be desirable in large code bases where the system becomes sluggish while you type. The delay can result in a longer execution time for the first IntelliSense operation on a file, but it can be helpful on slow or resource-constrained machines.

  Other consequences of disabling the feature include:

  • Background parsing for error reporting is disabled.
  • IntelliSense errors aren't indicated with squiggles.
  • IntelliSense errors aren't displayed in the Error List window.

• Automatically determine the maximum number of translation units to cache based upon available system memory: When selected (default), IntelliSense automatically tunes the Maximum number of translation units that will be kept active at a time for IntelliSense requests value based on available system RAM. This action automatically sets the maximum number of translation units to keep active at any one time for IntelliSense requests. If you prefer to specify the value manually, clear this option.

  For more information about translation units, see Phases of translation.

• Maximum number of translation units that will be kept active at a time for IntelliSense requests: Use this option to specify the maximum number of translation units to keep active at any one time for IntelliSense requests. The value must be between 2 and 64.

  When the Automatically determine the maximum number of translation units to cache based upon available system memory option is enabled, the value of this option is determined for you by the system and can't be changed manually. To change the value, first clear the Automatically determine the maximum number of translation units ... option.

• Show completion list for #include statements: When selected (default), IntelliSense provides an autocompletion list for #include statements.

• Use forward slash as the folder delimiter for #include completion statements: When selected (default), IntelliSense autocompletes #include statements when you specify the forward slash /. The default delimiter is backslash \. The compiler can accept either character, so use this option to indicate whether to use the forward slash for your code base.

  When the Show completion list for #include statements option isn't selected, this option isn't available.

• Colorize tokens based on IntelliSense classifications: When selected (default), IntelliSense uses token colorization based on standard classifications, including language keywords, strings, and comments.

• Expand snippets when tab is pressed: When selected (default), IntelliSense expands a snippet when you select Tab, regardless of whether the member list is shown. One exception for this behavior is when the shortcut key is assigned to the Edit.InvokeSnippetFromShortcut action.

• Enable IntelliSense for C++20 modules: When selected (default), IntelliSense provides code completion for modules. Enable this option if you use the module, import, and export declarations available in C++20.

• Enable IntelliSense for inactive platforms in folders and shared assets projects: When selected (default), IntelliSense features are enabled for inactive platforms in folders and shared assets projects.

• Maximum number of inactive platforms that will be processed for IntelliSense: Use this setting to specify the maximum number of inactive platforms that are processed for IntelliSense. The value must be between 1 and 16.

  When the Enable IntelliSense for inactive platforms in folders and shared assets projects option isn't selected, this option isn't available.

• Automatically generate precompiled headers for IntelliSense: When selected (default), IntelliSense uses the precompiled header, which speeds up some IntelliSense operations at the expense of a larger per-solution hard drive cache.

• Maximum size of the per-solution precompiled header cache in megabytes: Use this option to specify the maximum size of the per-solution cache in megabytes. The actual usage might fluctuate around the specified value.

  When the Automatically generate precompiled headers for IntelliSense option isn't selected, this option isn't available.

• Maximum total memory usage of an IntelliSense process in megabytes: Use this setting to specify the maximum total memory usage of an IntelliSense process in megabytes.

• Display a bar in the editor to configure IntelliSense inside templates: When selected (default), if the cursor is active within a template body, IntelliSense displays a bar in the editor that you can use to configure the IntelliSense attributes for the template.

• Style for #include suggestions: Use this option to specify the style for IntelliSense to use when providing suggestions for #include statements. Choose from Core Guidelines (default), Quotes, or Angle brackets.

Quick info

The following options are available in the C/C++ > IntelliSense > Quick info section.

• Show data structure's size and alignment in tooltips: When selected (default), IntelliSense shows the size and alignment of a data structure in tooltips. If you clear this option, the Show size and alignment for variables option isn't available.

• Show size and alignment for variables: When selected, IntelliSense shows the size and alignment for variables in tooltips. By default, this option isn't selected. If the Show data structure's size and alignment in tooltips option isn't selected, this option isn't available.

• Show help link: When selected (default), IntelliSense supports linking to online searches on the Quick Info tooltip.

• Use web search for help link: When selected (default), IntelliSense launches a web search with the specified search provider to support online searches in the Quick Info tooltip. If you disable the option (False), IntelliSense uses F1 Help.

• URL used for web searches: Use the option to specify the URL to target for online help on errors. By default, the value is set to https://www.bing.com/search?q={0}. IntelliSense replaces the {0} portion of the link with the token or error string from the tooltip.

• Doxygen tags to display on Quick Info tooltips: Use this option to identify the set of Doxygen command tags that IntelliSense can use when displaying Quick Info tooltips. By default, the set includes the param, tparam, returns, deprecated, and exception tags, in that order. Use the Add, Remove, and Move Up/Down actions to modify the list as needed.

Completion list

The following options are available in the C/C++ > IntelliSense > Completion list section.

• Automatically select matches after typing a scope or invoking the completion list: When selected (default), IntelliSense automatically selects the best entry after you type a scope operator or invoke the completion list. This approach keeps you from having to move the selection manually.

• Show suggestions as you type: When selected (default), IntelliSense shows suggestions as you type.

• Commit the item by pressing one of the commit characters: When selected, you can apply a suggestion by using any character specified in the Characters that will commit the selected suggestion option. By default, this option isn't selected.

  When the Show suggestions as you type option isn't enabled, this option isn't available.

• When an item is highlighted but not selected commit the item by pressing Tab: When selected (default), you can select Tab to commit a highlighted item.

• Characters that will commit the selected suggestion: Use this option to specify the characters you can enter to commit the highlighted suggestion. You can add or remove characters from this list: {}[]().,:;+-*/%&|^!=<>?@#\.

• Type of filtering: Use this option to set the type of matching algorithm for filtering. Choose from the following options:

  • Fuzzy (default): Find the most possible matches by using an algorithm similar to a spell-checker, which finds both approximate and identical matches.
  • Smart: Match substrings even if they're not at the start of a word.
  • Prefix: Only match identical substrings that start at the beginning of the word.
  • None: Don't use filtering.

• Show language keywords: When selected (default), IntelliSense shows language keywords like void, class, switch in suggestions.

• Show code snippets: When selected (default), IntelliSense shows code snippets in suggestions.

• Show inaccessible items: When selected, IntelliSense displays inaccessible member list items. By default, this option isn't selected.

• Replace '.' with '->' when applicable after committing an item: When selected (default), after IntelliSense commits an item, it replaces any period . character with an arrow -> (dash and angle bracket), as appropriate.

• Add a new line when pressing Enter to commit a fully typed word: When selected, after you select Enter at the end of a fully typed word to complete a commit, IntelliSense adds a new line. By default, this option isn't selected.

• Provide context-aware list of suggestions: When selected (default), IntelliSense shows a context-aware list of suggestions as you type. A maximum of 10 suggestions can be shown at a time.

• Provide extended context-aware list of suggestions for enum types: When selected (default), IntelliSense shows an extended list of context-aware suggestions when you use enums in switch case labels, return statements, and comparison operations. When the Provide context-aware list of suggestions option isn't enabled, this option isn't available.

Browsing and navigation

General options to configure browsing and navigation are available in the C/C++ > IntelliSense > Browsing & navigation section.

• Cache code browsing information: When selected (default), all browsing and navigation options, and all IntelliSense features are available.

  If you clear this option, all use of the code browsing database and all IntelliSense features except for #include Auto Complete are disabled.

• Enable updates to the code browsing database: When selected (default), updates can be performed while files are being edited.

  If you clear this option, the database is opened in read-only mode and no updates are performed while files are being edited. Most features continue to work. However, as edits are made, the data becomes stale leading to incorrect results.

• Update code browsing information as you type: When selected (default), the code browsing database is automatically updated when source files are modified.

  If you clear this option, the code browsing database isn't automatically updated when source files change. However, if you open Solution Explorer, open the shortcut menu for the project, and select Rescan Solution, outdated files are scanned and the database is updated.

• Recreate the code browsing database the next time the solution is loaded: When selected, Visual Studio recreates the code browsing database when the solution loads. The next time the solution loads, Visual Studio rebuilds the code browsing database. This option is then deselected, so the browsing database doesn't rebuild every time you load the solution.

• Interval to rescan solution (in minutes): Use this option to specify how often the solution is rescanned. The default value is 60 minutes. Specify a value between 0 and 5,000 minutes.

  While Visual Studio is rescanning the solution, file timestamps are checked to determine whether a file was changed outside of the IDE. It verifies that included file references are valid. (Changes made in the IDE are automatically tracked and files are updated.)

• Wait for the browsing database to be up-to-date when executing browsing operations: When selected, Visual Studio waits for the code browsing database to be up-to-date before doing browsing operations. By default, this option isn't selected.

• Show information for the selected code element in the properties window: When selected, Visual Studio shows information for the selected code element in the Properties tool window. By default, this option isn't selected.

• Choose how to highlight macros that are inside regions skipped by the browsing database: Use this option to specify how to highlight macros inside regions that the browsing database skips. Choose from Suggestion (default), Warning, Error, or None. For more information about hint files, see Hint files.

• Include skipped regions from external files when displaying browsing database errors: When selected, skipped regions from external files are included when Visual Studio displays browsing database errors. By default, this option isn't selected.

• Use fuzzy matching to provide search results: Rather than only finding exact matches, fuzzy matching finds similar strings or code snippets that might not exactly match the input. You might see results with variations like typos or different casing.

  When selected (default), Visual Studio returns both exact matches and approximate matches. If you clear this option, only exact matches are returned.

• Enable fuzzy match results when searching in the solution explorer: When selected (default), a search in Solution Explorer returns both exact matches and approximate matches for items in your solution. If you clear this option, the search returns only exact matches in your solution.

• Allow for fuzzy navigation to declarations or definitions after the signatures have changed: When selected (default), you can navigate to declarations or definitions whose signatures are changed. These enhancements let you access current declarations or definitions from older references based on outdated signatures.

  If you clear this option, you can't jump to a current declaration or definition from an older reference based on an outdated signature.

• Save code browsing information for external dependencies: Explicitly specified source and header files can reference external files such as afxwin.h, windows.h, atlbase.h, and so on. These external files aren't normally indexed. When selected (default), the browsing database indexes these files as well for features like Navigate To.

  If you clear this option, external dependencies aren't indexed, and some features aren't available, such as:

  • Periodically scan external dependencies and remove unused files from database
  • Evaluate external dependencies graph
  • Show external dependencies in solution explorer

• Periodically scan external dependencies and remove data for files that are no longer included from the code browsing database: When selected (default), Visual Studio periodically scans the external dependencies to remove data for files that are no longer referenced. For example, if a previously included file included an external dependency, and the included file is removed, the external dependency referenced by the removed file needs to be removed as well.

  If you clear this option, Visual Studio doesn't periodically rescan the solution to update the database.

  Note

  If you explicitly rescan the solution, your setting for this option is ignored. For more information, see the Rescan Solution Interval option.

• Evaluate external dependencies graph: In Solution Explorer, each project can contain an External Dependencies folder, which contains the list of all implicit files for that project. When selected (default), Visual Studio identifies the external dependencies for the project and creates or updates the folder. If you clear this option, Visual Studio doesn't update the folder contents.

• Show external dependencies in solution explorer: When selected (default), the External Dependencies folder for projects is visible in Solution Explorer. If you clear this option, the folder isn't visible.

Location for the browsing database

Options to configure the browsing database location are available in the C/C++ > IntelliSense > Browsing & navigation > Location section.

By default, the primary location for the code-browsing information and IntelliSense support files is the solution directory folder.

Use the following settings to specify a location to store the browsing database if the default location isn't available. When no location is specified, your temporary directory is used.

• Always use the specified custom location for the browsing database: When selected, Visual Studio always uses the secondary location specified in the Custom location for browsing database files option as the primary location for the browsing database. When this option isn't selected (default), Visual Studio uses the default primary location, which is the hidden .vs folder at the root of your solution folder.

• Custom location for browsing database files: Use this option to specify a custom folder for Visual Studio to use as the secondary location for the browsing database location.

  This folder is also used if the default primary location is currently unavailable. When no location is specified, Visual Studio uses the user's temporary directory as the default secondary location.

Errors

These options are available in the C/C++ > IntelliSense > Errors section.

• Show IntelliSense errors in the error list window: When selected (default), Visual Studio shows IntelliSense errors in the Error List window.

• Show IntelliSense errors in the editor: When selected (default), Visual Studio shows IntelliSense errors by underlining code in the editor with red squiggles.

• Suggest fixes for IntelliSense errors: When selected (default), Visual Studio suggests fixes for IntelliSense errors.

• Maximum number of threads to use for looking up suggestions: Use this option to specify the maximum number of threads for IntelliSense to use when looking up suggestions. The value must be between 1 and 16.

• Maximum number of errors to lookup fixes for: Use this option to specify the maximum number of errors for which IntelliSense should lookup fixes. The value must be between 1 and 1,000.

Refactoring

These options are available in the C/C++ > IntelliSense > Refactoring section.

• Offer suggestions to create missing function declarations or definitions: When selected (default), IntelliSense provides suggestions for creating missing function declarations or definitions.

• Choose how to highlight functions that can have their declaration or definition generated: Use this option to specify how IntelliSense should indicate missing function declarations or definitions that can be generated. Choose from Suggestion (default), Warning, Error, or Refactoring only. When the Offer suggestions to create missing function declarations or definitions option isn't selected, this option can't be selected.

• Navigation action for the generated code after a refactoring operation: Use this option to specify what the IDE should do after IntelliSense generates code for a refactor operation. Choose from Open document (default), Peek document, or None.

• Choose how to highlight types that can have member functions generated: Use this option to specify how IntelliSense should indicate that member functions can be generated for a type. Choose from Suggestion, Warning, Error, or Refactoring only (default).

• Choose how to highlight global functions that can be made static: Use this option to specify how IntelliSense should indicate that a global function can be made static. Choose from Suggestion (default), Warning, Error, or None.

• Choose how to highlight macro definitions that are able to be converted to equivalent constexpr definitions: Use this option to specify how IntelliSense should highlight macro definitions that can be converted to equivalent constexpr definitions. Choose from Suggestion (default), Warning, Error, or None.

Inlay hints

The following options are available in the C/C++ > IntelliSense > Inlay hints section.

• Enable background processing of inlay hints information: When selected (default), inlay hints provide more context about call sites and deduced types directly in the source code. When you enable this option, the other options in the section can be configured.

• Display inlay hints in the editor: When selected, IntelliSense displays the inlay hints in the editor. By default, this option isn't selected. When the Enable background processing of inlay hints information option isn't selected, this option can't be selected.

• Press Ctrl twice to toggle inlay hints: When selected, you can select Ctrl twice to toggle visibility of the inlay hints. By default, this option isn't selected. When the Enable background processing of inlay hints information option isn't selected, this option can't be selected.

• Show the deduced type when 'auto' is used in a declaration: When selected (default), IntelliSense shows the deduced type for a declaration declared auto. By default, this option is enabled. When the Enable background processing of inlay hints information option isn't selected, this option can't be selected.

• Type hints will cover the 'auto' keyword instead of being shown next to it: When selected, IntelliSense shows the hint for the deduced type in place of the auto keyword rather than next to the keyword. By default, this option isn't selected. When the Enable background processing of inlay hints information option isn't selected, this option can't be selected.

• Show parameter name inline at call sites: When selected (default), IntelliSense displays parameter names inline at the call site. This option is unavailable unless the Enable background processing of inlay hints information option is selected.

• Add '&' to hints to indicate when a parameter is passed by non-const reference: When selected (default), IntelliSense adds the ampersand & hint when a reference passes a parameter without the const keyword. This option is unavailable unless the Show parameter name inline at call sites option is selected.

• Don't show a hint when the argument text (including inline comments) contains the parameter name: When selected (default), IntelliSense doesn't show a hint when the argument text contains the parameter name, including when the text appears within inline comments. When the Show parameter name inline at call sites option isn't selected, this option can't be selected.

Non-project files

Options to configure IntelliSense for standalone, nonproject files are available in the C/C++ > IntelliSense > Non-project files section.

• Enable IntelliSense for standalone files that aren't part of an existing project: When selected (default), you can apply IntelliSense to standalone files that aren't part of an existing project. When this option is selected, you can configure the following options:

  • Show IntelliSense errors in the editor
  • Show IntelliSense errors in the error list
  • Suspend enabling IntelliSense for newly opened files while debugging

• Show IntelliSense errors in the editor: When selected, IntelliSense displays squiggles for errors in standalone nonproject files. By default, this option isn't selected. When the Enable IntelliSense for standalone files that aren't part of an existing project option is selected, this option is ignored and can't be selected.

• Show IntelliSense errors in the error list: When selected, IntelliSense errors from standalone nonproject files display in the Error List window. By default, this option isn't selected. When the Enable IntelliSense for standalone files that aren't part of an existing project option isn't selected, this option is ignored and can't be selected.

• Suspend enabling IntelliSense for newly opened files while debugging: When selected, IntelliSense isn't enabled for files that you open while debugging. This option is unavailable when the Enable IntelliSense for standalone files that aren't part of an existing project option isn't selected.

References

Options to support references for C and C++ projects are available in the C/C++ > IntelliSense > References section.

• Highlight references to the symbol under the cursor: When selected (default), Visual Studio highlights all references to the symbol that's currently under the cursor.

• Automatically determine the maximum number of find references threads to use based on system CPU cores count: When selected, the Maximum number of threads to use for finding references value is automatically tuned based on the number of CPU cores. If you prefer to specify the value manually, clear this option (default).

• Maximum number of threads to use for finding references: Use this option to specify the maximum number of threads the system can use for finding references. The value must be between 1 and 63.

  When the Automatically determine the maximum number of find references threads... option is selected, the value of this option is determined for you by the system.

Diagnostic logging

Options to support diagnostic logging for C and C++ are available in the C/C++ > IntelliSense > Diagnostic logging section.

• Log diagnostic information to the output window: When selected, Visual Studio sends diagnostic logging data to the output window.

• Logging level: Use this option to set the logging verbosity, from 0 (most quiet) to 5 (most verbose - default).

• Logging filter: Use this option to filter displayed event types by specifying the sum of any of the following event types. For example, to see Work Item (4) and Database (32) logs, enter 36 as the value.

  Value	Event type
  0	None (Default)
  1	General
  2	Idle
  4	WorkItem
  8	IntelliSense
  16	Assert
  32	Database
  64	Timing
  128	Statistics

  Depending on the value, you might need to exit and restart Visual Studio.

Related content

• Using IntelliSense