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C/C for Visual Studio Code (Preview) C/C support for Visual Studio Code is provided by a Microsoft C/C extension to enable cross-platform C and C development on Windows, Linux, and macOS. Getting started C/C compiler and debugger. The C/C extension does not include a C compiler or debugger.

In the previous lessons (3.6 - Using an integrated debugger: Stepping and 3.7 - Using an integrated debugger: Running and breakpoints), you learned how to use the debugger to watch the path of execution through your program.However, stepping through a program is only half of what makes the debugger useful. The debugger also lets you examine the value of variables as. This action does not advance the debugger. You can also use right-click menus from the Call Stack window to do other things. For example, you can insert breakpoints into specified functions, advance the debugger using Run to Cursor, and go examine source code. For more information, see How to: Examine the Call Stack.

Use the Debugger to step through code, set watches and breakpoints, live edit your code and inspect your caches. Test and troubleshoot your code by:

• Browsing and searching code from your loaded source files
• Controlling the execution flow as you step through your code
• Managing page storage resources, including the service workers and cache, cookies and web storage
• Setting breakpoints and live editing your code as it runs
• Tracking and editing local variables as you debug
• Hiding or showing asynchronous code and library code from your callstack as needed
• Adding specialized breakpoints for XmlHttpRequests, events and DOM mutations

There are three ways to begin a debugging session.

1. Set a breakpoint. When the execution of your code reaches it, you'll enter the debugger and be able to step through your code.
2. Initiate a break in code. Click the Break (pause icon) toolbar button or Ctrl+Shift+B. The debugger will break on the next statement of execution.
3. Set exception behavior. Use the Change exception behavior menu (Ctrl+Shift+E) to break into the debugger when your code throws an exception. By default, the debugger is set to Never break on exceptions, but they are logged to the console.

Resource picker

Often the first step in debugging is to set breakpoints in the code you're looking to troubleshoot. You can find all the code files currently loaded by the page from the Resource picker pane, including .html, .css and .js files.

Clicking on a file entry will open a tab for that file in the Debug window and bold the text of the file name to indicate this (as devtools-guide file name is in the illustration above). You can then set breakpoints within that file from the Debug window.

From the Resource picker context menu, you can also mark a file as library code (Ctrl+L), giving you the option to skip over that code in the debugger and hide it from the Call stack pane. Clicking (or Ctrl+L) again will toggle the file back to its previous value as my code or library code.

File search

Use the Find in files command (Ctrl+Shift+F) when you have a specific string of code you're trying to find in the source. The toolbar provides different search options, including regular expressions. Clicking on a search result will focus the Debug window on the specified file and line.

Debug window

The Debug window is where you set your breakpoints, step through code, and live edit your script as you debug. Click to the left of any script command to add (or remove) a Breakpoint. Use the right-click context menu or Breakpoints pane to Add a condition to the breakpoint by supplying a logical expression that causes the debugger to break if it evaluates True at that location.

Other features of the debug window include controls for:

1. Code editing

You can edit your JavaScript live during a debugging session. Once you make your changes, click Save (Ctrl+S) to test your changes next time that section of code runs. If you have unsaved code changes, an asterisk (*) will appear before the file name in the Debug window tab.

Click the Compare document to original button to view the diff of what you changed.

Please be aware of the following constraints:

• Script editing only works in external .js files (and not embedded <script> within .html)
• Edits are saved in memory and flushed when the document is reloaded, thus you won't be able to run edits inside a DOMContentLoaded handler, for example
• Currently there's no way (such as a Save As option) to save your edits to disk from the DevTools

2.Code formatting

Use these controls to format minified code for better readability as you debug:

Pretty print (Ctrl+Shift+P)

Adds line breaks and curly brace alignment per JavaScript conventions. Even compressed code that's been made more readable with this option may have function, selector, and variable names that are much different than in your original source code. In these cases, the Toggle source maps option might be available.

Word wrap (Alt+W)

Adjusts code to fit within the current margins of the debug window (eliminating the need for horizontal scrolling).

3. Code scoping

You can direct the debugger to ignore certain files with the Mark as library code (Ctrl+L) button. By default, the Debug just my code toolbar button is on, meaning that the debugger will skip over any files that you mark as library code and they will not appear in the debugger call stack. Depressing the button (Mark as my code, Ctrl+L) will remove this flag.

For keeping track of libraries across debugging sessions, you can edit these files to maintain a default list or add wildcards for a domain or file type:

Source maps

You will see the Toggle source maps button enabled for code written in a language that compiles to JavaScript or CSS and that provides a source map (an intermediate file mapping to the original source). This option directs the debugger to present the original source to use for debugging (rather than the compiled file that's actually running in the browser).

The DevTools will check if the compiler that generated the JavaScript file included a comment with the name of the map file. For example, if a compiler compressed myfile.js to myfile.min.js, it might also generate a map file, myfile.min.js.map and include a comment in the compressed file like this:

If the DevTools can't find the map automatically, you can choose a source map for that file. Right-click the file's tab to find the Choose source map option.

Toolbar

Use the debugger Toolbar to control how you step through code, and what code to step through or ignore. From here you can also do a full text search across your code files for specific strings.

1. Continue (F5) / Break (Ctrl+Shift+B)

Continue (F5) continues code execution to the next breakpoint. Holding down F5 will repeatedly move past breaks until you release it.

Break (Ctrl+Shift+B) will break into the debugger after running the next statement.

2. Step functions (F11, Ctrl+F10, Shift+F11)

Step into (F11) steps into the function being called.

Step over (Ctrl+F10) steps over the function being called.

Step out (Shift+F11) steps out of the current function and into the calling function.

The debugger will step to the next statement if it is not at a function when these commands are used.

3. Break on new worker (Ctrl+Shift+W)

Breaks on the creation of a new web worker.

4. Exception control

Change exception behavior (Ctrl+Shift+E) opens options to change how the debugger reacts to exceptions. By default exceptions are ignored by the debugger and logged to the Console. You can choose to Break on all exceptions, or just those not being handled by try...catch statements in your code (Break on unhandled exceptions).

5. View search results

(Currently disabled.) Show/Hide results toggles the display of Find in files search results.

6. Find in files (Ctrl+F)

Find in files (Ctrl+F) runs a text search through all the loaded files within the Resource picker. If the text is found, it opens the first file matching the search string. Pressing Enter or F3 takes you to the next match.

Dev C++ Debugger

7. Debug just my code (Ctrl+J)

Debug just my code (Ctrl+J) acts as a toggle to include or exclude all the files that have been marked as library code as you step through the debugger.

8. Debugger connection

Disconnect/Connect debugger is essentially the on/off switch for the debugger.

Watches

Use the Watches pane to browse a catalog of all objects and variables (Locals), both in the local and global scope, available to the statement that is the focus of the current break in the debugger.

You can track the value of specific variables as they pass in and out of scope by adding a watch (Add watch, Ctrl+W) and modify any editable values by double-clicking on it or by selecting Edit value from the Context menu. Clear your watches using the Delete (Ctrl+D) / Delete all buttons or from the context menu.

Details

The Details pane includes the Callstack, Breakpoints and DOM breakpoints tabs.

Call stack

The Call stack tab shows the chain of functions that led to the current point of execution. The current function appears at the top, and the calling functions appear below it in reverse order.

The Show/Hide library frames button (Ctrl+Shift+J) toggles the output of library code from the call stack. Use the Library code option (Ctrl+L) from the right-click Context menu to mark (or unmark) the source of the selected frame as library code.

The Show/Hide async frames button toggles the display of roots for asynchronous function calls.

Breakpoints

From the Breakpoints tab, you can manage you breakpoints and event tracepoints, including setting conditions, disabling and deleting them.

Here's a summary of the different types of breakpoints you can use for debugging.

Conditional breakpoints and tracepoints have access to all the local and global variables currently in scope when they break into the debugger.

DOM breakpoints

Manage your DOM mutation breakpoints from the DOM breakpoints tab, including disabling, deleting and rebinding them. DOM breakpoints can be set from the HTML tree view in the Elements panel.

The DOM breakpoints tab in the Debugger provides equivalent functionality to the DOM breakpoints* tab on the Elements panel.

Here's more on the different types of DOM breakpoints.

Dev C++ 5.11

Shortcuts

Toolbar shortcuts

Resource picker shortcuts

Debug window shortcuts

Shortcuts for Watches pane

Shortcuts for Details pane

After you have set up the basics of your debugging environment as specified in the configuration tutorials for each target compiler/platform, you can learn more details about debugging C/C++ in this section.

Visual Studio Code supports the following debuggers for C/C++ depending on the operating system you are using:

• Linux: GDB
• macOS: LLDB or GDB
• Windows: the Visual Studio Windows Debugger or GDB (using Cygwin or MinGW)

Windows debugging with GDB

You can debug Windows applications created using Cygwin or MinGW by using VS Code. To use Cygwin or MinGW debugging features, the debugger path must be set manually in the launch configuration (launch.json). To debug your Cygwin or MinGW application, add the miDebuggerPath property and set its value to the location of the corresponding gdb.exe for your Cygwin or MinGW environment.

For example:

Cygwin/MinGW debugging on Windows supports both attach and launch debugging scenarios.

To learn more, see Configuring C/C++ debugging.

If you are debugging with GDB on Windows, see Windows Debugging with MinGW64.

Conditional breakpoints

Conditional breakpoints enable you to break execution on a particular line of code only when the value of the condition is true. To set a conditional breakpoint, right-click on an existing breakpoint and select Edit Breakpoint. This opens a small peek window where you can enter the condition that must evaluate to true in order for the breakpoint to be hit during debugging.

In the editor, conditional breakpoints are indicated by a breakpoint symbol that has a black equals sign inside of it. You can place the cursor over a conditional breakpoint to show its condition.

Function breakpoints

Function breakpoints enable you to break execution at the beginning of a function instead of on a particular line of code. To set a function breakpoint, on the Run view right-click inside the Breakpoints section, then choose Add Function Breakpoint and enter the name of the function on which you want to break execution.

Expression evaluation

VS Code supports expression evaluation in several contexts:

• You can type an expression into the Watch section of the Run view and it will be evaluated each time a breakpoint is hit.
• You can type an expression into the Debug Console and it will be evaluated only once.
• You can evaluate any expression that appears in your code while you're stopped at a breakpoint.

Expressions in the Watch section take effect in the application being debugged; an expression that modifies the value of a variable will modify that variable for the duration of the program.

Multi-threaded debugging

The C/C++ extension for VS Code has the ability to debug multi-threaded programs. All threads and their call stacks appear in the Call Stack section:

Memory dump debugging

The C/C++ extension for VS Code also has the ability to debug memory dumps. To debug a memory dump, open your launch.json file and add the coreDumpPath (for GDB or LLDB) or dumpPath (for the Visual Studio Windows Debugger) property to the C++ Launch configuration, set its value to be a string containing the path to the memory dump. This will even work for x86 programs being debugged on an x64 machine.

Additional symbols

If there are additional directories where the debugger can find symbol files (for example, .pdb files for the Visual Studio Windows Debugger), they can be specified by adding the additionalSOLibSearchPath (for GDB or LLDB) or symbolSearchPath (for the Visual Studio Windows Debugger).

For example:

or

Locate source files

The source file location can be changed if the source files are not located in the compilation location. This is done by simple replacement pairs added in the sourceFileMap section. The first match in this list will be used.

For example:

GDB, LLDB, and MI Commands (GDB/LLDB)

For the C++ (GDB/LLDB) debugging environment, you can execute GDB, LLDB and MI commands directly through the debug console with the -exec command, but be careful, executing commands directly in the debug console is untested and might crash VS Code in some cases.

Other debugging features

• Unconditional breakpoints
• Watch window
• Call stack
• Stepping

For more information on debugging with VS Code, see this introduction to debugging in VS Code.

Known limitations

Symbols and code navigation

All platforms:

• Because the extension doesn't parse function bodies, Peek Definition and Go to Definition don't work for symbols defined inside the body of a function.

Debugging

Windows:

• GDB on Cygwin and MinGW cannot break a running process. To set a breakpoint when the application is running (not stopped under the debugger), or to pause the application being debugged, press Ctrl-C in the application's terminal.
• GDB on Cygwin cannot open core dumps.

C++ Debugger Linux

Linux:

• GDB needs elevated permissions to attach to a process. When using attach to process, you need to provide your password before the debugging session can begin.

macOS:

• LLDB:
  • When debugging with LLDB, if the Terminal window is closed while in break mode, debugging does not stop. Debugging can be stopped by pressing the Stop button.
  • When debugging is stopped the Terminal window is not closed.
• GDB:
  • Additional manual install steps are required to use GDB on macOS. See Manual Installation of GDB for OS X in the README.
  • When attaching to a process with GDB, the application being debugged cannot be interrupted. GDB will only bind breakpoints set while the application is not running (either before attaching to the application, or while the application is in a stopped state). This is due to a bug in GDB.
  • Core dumps cannot be loaded when debugging with GDB because GDB does not support the core dump format used in macOS.
  • When attached to a process with GDB, break-all will end the process.

Next steps

Dev C++ For Windows 10

Read on to find out about:

• Basic Editing - Learn about the powerful Visual Studio Code editor.
• Code Navigation - Move quickly through your source code.
• Tasks - use tasks to build your project and more
• Debugging - find out about the Visual Studio Code debugger

Free C++ Debugger

If you have any other questions or run into any issues, please file an issue on GitHub.