Как добавить gcc в path windows

Using GCC with MinGW

In this tutorial, you configure Visual Studio Code to use the GCC C++ compiler (g++) and GDB debugger from mingw-w64 to create programs that run on Windows.

After configuring VS Code, you will compile and debug a simple Hello World program in VS Code. This tutorial does not teach you about GCC, GDB, Mingw-w64, or the C++ language. For those subjects, there are many good resources available on the Web.

If you have any problems, feel free to file an issue for this tutorial in the VS Code documentation repository.

Prerequisites

To successfully complete this tutorial, you must do the following steps:

1. Install Visual Studio Code.

2. Install the C/C++ extension for VS Code. You can install the C/C++ extension by searching for ‘c++’ in the Extensions view (⇧⌘X (Windows, Linux Ctrl+Shift+X)).

   

3. Get the latest version of Mingw-w64 via MSYS2, which provides up-to-date native builds of GCC, Mingw-w64, and other helpful C++ tools and libraries. You can download the latest installer from the MSYS2 page or use this link to the installer.

4. Follow the Installation instructions on the MSYS2 website to install Mingw-w64. Take care to run each required Start menu and pacman command.

5. Install the Mingw-w64 toolchain (pacman -S --needed base-devel mingw-w64-x86_64-toolchain). Run the pacman command in a MSYS2 terminal. Accept the default to install all the members in the toolchain group.

6. Add the path to your Mingw-w64 bin folder to the Windows PATH environment variable by using the following steps:

   1. In the Windows search bar, type ‘settings’ to open your Windows Settings.
   2. Search for Edit environment variables for your account.
   3. Choose the Path variable in your User variables and then select Edit.
   4. Select New and add the Mingw-w64 destination folder path to the system path. The exact path depends on which version of Mingw-w64 you have installed and where you installed it. If you used the settings above to install Mingw-w64, then add this to the path: C:msys64mingw64bin.
   5. Select OK to save the updated PATH. You will need to reopen any console windows for the new PATH location to be available.

Check your MinGW installation

To check that your Mingw-w64 tools are correctly installed and available, open a new Command Prompt and type:

gcc --version
g++ --version
gdb --version

1. If you don’t see the expected output or g++ or gdb is not a recognized command, make sure your PATH entry matches the Mingw-w64 binary location where the compilers are located. If the compilers do not exist at that PATH entry, make sure you followed the instructions on the MSYS2 website to install Mingw-w64.
2. If gcc has the correct output but not gdb, then you need to install the packages you are missing from the Mingw-w64 toolset.
   • Missing the mingw-w64-gdb package is one cause of the «The value of miDebuggerPath is invalid.» message upon attempted compilation if your PATH is correct.

Create Hello World

From a Windows command prompt, create an empty folder called projects where you can place all your VS Code projects. Then create a sub-folder called helloworld, navigate into it, and open VS Code in that folder by entering the following commands:

mkdir projects
cd projects
mkdir helloworld
cd helloworld
code .

The «code .» command opens VS Code in the current working folder, which becomes your «workspace». Accept the Workspace Trust dialog by selecting Yes, I trust the authors since this is a folder you created.

As you go through the tutorial, you will see three files created in a .vscode folder in the workspace:

• tasks.json (build instructions)
• launch.json (debugger settings)
• c_cpp_properties.json (compiler path and IntelliSense settings)

Add a source code file

In the File Explorer title bar, select the New File button and name the file helloworld.cpp.

Add hello world source code

Now paste in this source code:

#include <iostream>
#include <vector>
#include <string>

using namespace std;

int main()
{
    vector<string> msg {"Hello", "C++", "World", "from", "VS Code", "and the C++ extension!"};

    for (const string& word : msg)
    {
        cout << word << " ";
    }
    cout << endl;
}

Now press ⌘S (Windows, Linux Ctrl+S) to save the file. Notice how the file you just added appears in the File Explorer view (⇧⌘E (Windows, Linux Ctrl+Shift+E)) in the side bar of VS Code:

You can also enable Auto Save to automatically save your file changes, by checking Auto Save in the main File menu.

The Activity Bar on the far left lets you open different views such as Search, Source Control, and Run. You’ll look at the Run view later in this tutorial. You can find out more about the other views in the VS Code User Interface documentation.

Note: When you save or open a C++ file, you may see a notification from the C/C++ extension about the availability of an Insiders version, which lets you test new features and fixes. You can ignore this notification by selecting the X (Clear Notification).

Explore IntelliSense

In your new helloworld.cpp file, hover over vector or string to see type information. After the declaration of the msg variable, start typing msg. as you would when calling a member function. You should immediately see a completion list that shows all the member functions, and a window that shows the type information for the msg object:

You can press the Tab key to insert the selected member; then, when you add the opening parenthesis, you will see information about any arguments that the function requires.

Run helloworld.cpp

Remember, the C++ extension uses the C++ compiler you have installed on your machine to build your program. Make sure you have a C++ compiler installed before attempting to run and debug helloworld.cpp in VS Code.

1. Open helloworld.cpp so that it is the active file.

2. Press the play button in the top right corner of the editor.

   

3. Choose C/C++: g++.exe build and debug active file from the list of detected compilers on your system.

   

You’ll only be asked to choose a compiler the first time you run helloworld.cpp. This compiler will be set as the «default» compiler in tasks.json file.

1. After the build succeeds, your program’s output will appear in the integrated Terminal.

   

The first time you run your program, the C++ extension creates tasks.json, which you’ll find in your project’s .vscode folder. tasks.json stores build configurations.

Your new tasks.json file should look similar to the JSON below:

{
  "tasks": [
    {
      "type": "cppbuild",
      "label": "C/C++: g++.exe build active file",
      "command": "C:\msys64\mingw64\bin\g++.exe",
      "args": [
        "-fdiagnostics-color=always",
        "-g",
        "${file}",
        "-o",
        "${fileDirname}\${fileBasenameNoExtension}.exe"
      ],
      "options": {
        "cwd": "${fileDirname}"
      },
      "problemMatcher": ["$gcc"],
      "group": {
        "kind": "build",
        "isDefault": true
      },
      "detail": "Task generated by Debugger."
    }
  ],
  "version": "2.0.0"
}

Note: You can learn more about tasks.json variables in the variables reference.

The command setting specifies the program to run; in this case that is g++.
The args array specifies the command-line arguments that will be passed to g++. These arguments must be specified in the order expected by the compiler.

This task tells g++ to take the active file (${file}), compile it, and create an executable file in the current directory (${fileDirname}) with the same name as the active file but with the .exe extension (${fileBasenameNoExtension}.exe), resulting in helloworld.exe for our example.

The label value is what you will see in the tasks list; you can name this whatever you like.

The detail value is what you will as the description of the task in the tasks list. It’s highly recommended to rename this value to differentiate it from similar tasks.

From now on, the play button will read from tasks.json to figure out how to build and run your program. You can define multiple build tasks in tasks.json, and whichever task is marked as the default will be used by the play button. In case you need to change the default compiler, you can run Tasks: Configure default build task. Alternatively you can modify the tasks.json file and remove the default by replacing this segment:

    "group": {
        "kind": "build",
        "isDefault": true
    },

with this:

    "group": "build",

Modifying tasks.json

You can modify your tasks.json to build multiple C++ files by using an argument like "${workspaceFolder}/*.cpp" instead of ${file}.This will build all .cpp files in your current folder. You can also modify the output filename by replacing "${fileDirname}\${fileBasenameNoExtension}.exe" with a hard-coded filename (for example "${workspaceFolder}\myProgram.exe").

Debug helloworld.cpp

1. Go back to helloworld.cpp so that it is the active file.
2. Set a breakpoint by clicking on the editor margin or using F9 on the current line.
   
3. From the drop-down next to the play button, select Debug C/C++ File.
   
   
4. Choose C/C++: g++ build and debug active file from the list of detected compilers on your system (you’ll only be asked to choose a compiler the first time you run/debug helloworld.cpp).
   

The play button has two modes: Run C/C++ File and Debug C/C++ File. It will default to the last-used mode. If you see the debug icon in the play button, you can just click the play button to debug, instead of using the drop-down.

Explore the debugger

Before you start stepping through the code, let’s take a moment to notice several changes in the user interface:

• The Integrated Terminal appears at the bottom of the source code editor. In the Debug Output tab, you see output that indicates the debugger is up and running.

• The editor highlights the line where you set a breakpoint before starting the debugger:

  

• The Run and Debug view on the left shows debugging information. You’ll see an example later in the tutorial.

• At the top of the code editor, a debugging control panel appears. You can move this around the screen by grabbing the dots on the left side.

  

Step through the code

Now you’re ready to start stepping through the code.

1. Click or press the Step over icon in the debugging control panel.

   

   This will advance program execution to the first line of the for loop, and skip over all the internal function calls within the vector and string classes that are invoked when the msg variable is created and initialized. Notice the change in the Variables window on the left.

   

   In this case, the errors are expected because, although the variable names for the loop are now visible to the debugger, the statement has not executed yet, so there is nothing to read at this point. The contents of msg are visible, however, because that statement has completed.

2. Press Step over again to advance to the next statement in this program (skipping over all the internal code that is executed to initialize the loop). Now, the Variables window shows information about the loop variables.

3. Press Step over again to execute the cout statement. (Note that as of the March 2019 release, the C++ extension does not print any output to the Debug Console until the loop exits.)

4. If you like, you can keep pressing Step over until all the words in the vector have been printed to the console. But if you are curious, try pressing the Step Into button to step through source code in the C++ standard library!

   

   To return to your own code, one way is to keep pressing Step over. Another way is to set a breakpoint in your code by switching to the helloworld.cpp tab in the code editor, putting the insertion point somewhere on the cout statement inside the loop, and pressing F9. A red dot appears in the gutter on the left to indicate that a breakpoint has been set on this line.

   

   Then press F5 to start execution from the current line in the standard library header. Execution will break on cout. If you like, you can press F9 again to toggle off the breakpoint.

   When the loop has completed, you can see the output in the Integrated Terminal, along with some other diagnostic information that is output by GDB.

   

Set a watch

Sometimes you might want to keep track of the value of a variable as your program executes. You can do this by setting a watch on the variable.

1. Place the insertion point inside the loop. In the Watch window, click the plus sign and in the text box, type word, which is the name of the loop variable. Now view the Watch window as you step through the loop.

   

2. Add another watch by adding this statement before the loop: int i = 0;. Then, inside the loop, add this statement: ++i;. Now add a watch for i as you did in the previous step.

3. To quickly view the value of any variable while execution is paused on a breakpoint, you can hover over it with the mouse pointer.

   

Customize debugging with launch.json

When you debug with the play button or F5, the C++ extension creates a dynamic debug configuration on the fly.

There are cases where you’d want to customize your debug configuration, such as specifying arguments to pass to the program at runtime. You can define custom debug configurations in a launch.json file.

To create launch.json, choose Add Debug Configuration from the play button drop-down menu.

You’ll then see a dropdown for various predefined debugging configurations. Choose C/C++: g++.exe build and debug active file.

VS Code creates a launch.json file, which looks something like this:

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "C/C++: g++.exe build and debug active file",
      "type": "cppdbg",
      "request": "launch",
      "program": "${fileDirname}\${fileBasenameNoExtension}.exe",
      "args": [],
      "stopAtEntry": false,
      "cwd": "${fileDirname}",
      "environment": [],
      "externalConsole": false,
      "MIMode": "gdb",
      "miDebuggerPath": "C:\msys64\mingw64\bin\gdb.exe",
      "setupCommands": [
        {
          "description": "Enable pretty-printing for gdb",
          "text": "-enable-pretty-printing",
          "ignoreFailures": true
        }
      ],
      "preLaunchTask": "C/C++: g++.exe build active file"
    }
  ]
}

In the JSON above, program specifies the program you want to debug. Here it is set to the active file folder (${fileDirname}) and active filename with the .exe extension (${fileBasenameNoExtension}.exe), which if helloworld.cpp is the active file will be helloworld.exe. The args property is an array of arguments to pass to the program at runtime.

By default, the C++ extension won’t add any breakpoints to your source code and the stopAtEntry value is set to false.

Change the stopAtEntry value to true to cause the debugger to stop on the main method when you start debugging.

From now on, the play button and F5 will read from your launch.json file when launching your program for debugging.

C/C++ configurations

If you want more control over the C/C++ extension, you can create a c_cpp_properties.json file, which will allow you to change settings such as the path to the compiler, include paths, C++ standard (default is C++17), and more.

You can view the C/C++ configuration UI by running the command C/C++: Edit Configurations (UI) from the Command Palette (⇧⌘P (Windows, Linux Ctrl+Shift+P)).

This opens the C/C++ Configurations page. When you make changes here, VS Code writes them to a file called c_cpp_properties.json in the .vscode folder.

Here, we’ve changed the Configuration name to GCC, set the Compiler path dropdown to the g++ compiler, and the IntelliSense mode to match the compiler (gcc-x64).

Visual Studio Code places these settings in .vscodec_cpp_properties.json. If you open that file directly, it should look something like this:

{
  "configurations": [
    {
      "name": "GCC",
      "includePath": ["${workspaceFolder}/**"],
      "defines": ["_DEBUG", "UNICODE", "_UNICODE"],
      "windowsSdkVersion": "10.0.18362.0",
      "compilerPath": "C:/msys64/mingw64/bin/g++.exe",
      "cStandard": "c17",
      "cppStandard": "c++17",
      "intelliSenseMode": "windows-gcc-x64"
    }
  ],
  "version": 4
}

You only need to add to the Include path array setting if your program includes header files that are not in your workspace or in the standard library path.

Compiler path

The extension uses the compilerPath setting to infer the path to the C++ standard library header files. When the extension knows where to find those files, it can provide features like smart completions and Go to Definition navigation.

The C/C++ extension attempts to populate compilerPath with the default compiler location based on what it finds on your system. The extension looks in several common compiler locations.

The compilerPath search order is:

• First check for the Microsoft Visual C++ compiler
• Then look for g++ on Windows Subsystem for Linux (WSL)
• Then g++ for Mingw-w64.

If you have Visual Studio or WSL installed, you may need to change compilerPath to match the preferred compiler for your project. For example, if you installed Mingw-w64 version 8.1.0 using the i686 architecture, Win32 threading, and sjlj exception handling install options, the path would look like this: C:Program Files (x86)mingw-w64i686-8.1.0-win32-sjlj-rt_v6-rev0mingw64bing++.exe.

Troubleshooting

MSYS2 is installed, but g++ and gdb are still not found

You must follow the steps on the MSYS2 website and use the MSYS CLI to install Mingw-w64, which contains those tools. You will also need to install the full Mingw-w64 toolchain (pacman -S --needed base-devel mingw-w64-x86_64-toolchain) to get the gdb debugger.

MinGW 32-bit

If you need a 32-bit version of the MinGW toolset, consult the Downloading section on the MSYS2 wiki. It includes links to both 32-bit and 64-bit installation options.

Next steps

• Explore the VS Code User Guide.
• Review the Overview of the C++ extension.
• Create a new workspace, copy your .vscode JSON files to it, adjust the necessary settings for the new workspace path, program name, and so on, and start coding!

5/13/2022

I am using Visual Studio Code on Windows 10 and I am trying to build a program (called Bus from the source file Bus.cpp) with g++ from MinGW. I modified the tasks.json file using various methods that I have read from previous threads. I am providing screenshots of the tasks.json file and the results after building (ctrl + shift + b). I am also providing my questions below.

Method 1

Method 2

Method 3

Method 4

Question 1) I want to be able to build and create a program called «bus» using method 1. However, I have to replace «g++» with the directory path of the MinGW’s g++ compiler (as shown in method 2). What do I have to do in order to just put «g++» instead of the path to MinGW’s g++.exe?

Question 2) It looks like it compiled using methods 2 and 4 which provide the directory path to MinGW’s g++ compiler but I do not see the built program called «bus» even though I used «-o bus» in the command. Why do I not see it?

EDIT TO SHOW CODES:

First Method tasks.json file:

{
    // See https://go.microsoft.com/fwlink/?LinkId=733558
    // for the documentation about the tasks.json format
    "version": "2.0.0",
    "tasks": [
        {
            "label": "build",
            "type": "shell",
            "command": "g++ -g bus.cpp -o bus",
            "group": {
                "kind": "build",
                "isDefault": true
            }
        }
    ]
}

First Method resulting output:

> Executing task: g++ -g bus.cpp -o bus <

g++ : The term 'g++' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name,
or if a path was included, verify that the path is correct and try again.
At line:1 char:1
+ g++ -g bus.cpp -o bus
+ ~~~
    + CategoryInfo          : ObjectNotFound: (g++:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

The terminal process terminated with exit code: 1

Terminal will be reused by tasks, press any key to close it.

Second Method tasks.json file:

{
    // See https://go.microsoft.com/fwlink/?LinkId=733558
    // for the documentation about the tasks.json format
    "version": "2.0.0",
    "tasks": [
        {
            "label": "build",
            "type": "shell",
            "command": "C:/MinGW/bin/g++.exe -g bus.cpp -o bus",
            "group": {
                "kind": "build",
                "isDefault": true
            }
        }
    ]
}

Second Method resulting output:

> Executing task: C:/MinGW/bin/g++.exe -g bus.cpp -o bus <

The terminal process terminated with exit code: 1

Terminal will be reused by tasks, press any key to close it.

Third Method tasks.json file:
{
    // See https://go.microsoft.com/fwlink/?LinkId=733558
    // for the documentation about the tasks.json format
    "version": "2.0.0",
    "tasks": [
        {
            "label": "build",
            "type": "shell",
            "command": "g++",
            "args": [
                "-g", "bus.cpp", "-o", "bus"
            ],
            "group": {
                "kind": "build",
                "isDefault": true
            }
        }
    ]
}

Third Method resulting output:

    > Executing task: g++ -g bus.cpp -o bus <

g++ : The term 'g++' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name,
or if a path was included, verify that the path is correct and try again.
At line:1 char:1
+ g++ -g bus.cpp -o bus
+ ~~~
    + CategoryInfo          : ObjectNotFound: (g++:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

The terminal process terminated with exit code: 1

Terminal will be reused by tasks, press any key to close it.

Fourth Method tasks.json file:

{
    // See https://go.microsoft.com/fwlink/?LinkId=733558
    // for the documentation about the tasks.json format
    "version": "2.0.0",
    "tasks": [
        {
            "label": "build",
            "type": "shell",
            "command": "C:/MinGW/bin/g++",
            "args": [
                "-g", "bus.cpp", "-o", "bus"
            ],
            "group": {
                "kind": "build",
                "isDefault": true
            }
        }
    ]
}

Fourth Method resulting output:

    > Executing task: C:/MinGW/bin/g++ -g bus.cpp <

The terminal process terminated with exit code: 1

Terminal will be reused by tasks, press any key to close it.

11 mins read

Follow these steps to install g++ (the GNU C++ compiler) for Windows. There is no room for creativity here; you must follow the directions exactly.

1. Pick the drive and a folder in which you want to install g++. I’ll assume that it is C:, but you can choose a different one. If you choose a different drive or a different folder, you’ll need to adapt the directions below accordingly.
2. Download full.exe, an about 14 megabyte executable, to C:full.exe by right-clicking on the link. Use Save Link As… or Save Target As… Be sure the browser saves the file as C:full.exe.
3. Run the downloaded executable. This will install g++ (and a lot of other things that you don’t really need) on your hard drive. Go to the C: drive using Windows Explorer and double-click on full.exe. Or, open a DOS command prompt window (Start > Programs > Command Prompt), connect to the C: drive using the cd command, and type full.
4. Locate where the bin folder was created for the g++ installation. On my Windows machine, it was created in the following path: C:cygnuscygwin-b20H-i586-cygwin32bin You now should add it to the PATH environment variable. You do that by following: Start -> Control Panel -> System -> Advanced -> Environment Variables At this point you can see the PATH variable either in the User Variables or in the System Variables. Add the g++ path into the PATH variable. You add it to the end of the existing value separated by a semicolon (‘;’). Make sure that you do not lose the original value. You are just appending more to the end separated by a semicolon.
5. Restart your computer. A Cygnus Solutions entry will appear in your Programs menu, and an icon may appear on your desktop. Don’t use them! You will use it using the g++ command on a DOS command prompt as explained below.

You should now be able to run g++ from a DOS command prompt window. For example, to compile a file called C:minehello.cpp, connect to the C:mine folder and enter

g++ -g hello.cpp -o hello -lm

You’ll then be able to run the compiled program by entering hello in the DOS command prompt window.

If you’ve installed Emacs as described here, you will also be able to run g++ from Emacs. If, when you do this, Emacs tries to compile with the command make -k, you made a mistake during the Emacs installation. (If you try to compile a C program, e.g., hello.c instead of a C++ program, e.g., hello.cpp, it will try to make -k. In that case enter the compile command, gcc -g hello.c -o hello -lm, manually. After you try it manually once, from the second time on it will do the right thing automatically.) If you want to learn how to run g++ on emacs, see here.

If you’d like to learn more about where this free compiler came from, we downloaded it from an older site of http://sourceware.org/cygwin/.

If you wish to clean up a little, you may delete the file: full.exe at this point. Your g++ compiler is installed under C:cygnus.

Several modern C++ features are currently missing from Visual Studio Express, and from the system GCC compiler provided with many of today’s Linux distributions. Generic lambdas – also known as polymorphic lambdas – are one such feature. This feature is, however, available in the latest versions of GCC and Clang.

The following guide will help you install the latest GCC on Windows, so you can experiment with generic lambdas and other cutting-edge C++ features. You’ll need to compile GCC from sources, but that’s not a problem. Depending on the speed of your machine, you can have the latest GCC up and running in as little as 15 minutes.

The steps are:

1. Install Cygwin, which gives us a Unix-like environment running on Windows.
2. Install a set of Cygwin packages required for building GCC.
3. From within Cygwin, download the GCC source code, and build and install it.
4. Test the new GCC compiler in C++14 mode using the -std=c++14 option.

You can also install native GCC compilers from the MinGW-w64 project without needing Cygwin.

1. Install Cygwin

First, download and run either the 32- or 64-bit version of the Cygwin installer, depending on your version of Windows. Cygwin’s setup wizard will walk you through a series of steps. If your machine is located behind a proxy server, make sure to check “Use Internet Explorer Proxy Settings” when you get to the “Select Your Internet Connection” step.

When you reach the “Select Packages” step (shown below), don’t bother selecting any packages yet. Just go ahead and click Next. We’ll add additional packages from the command line later.

After the Cygwin installer completes, it’s very important to keep the installer around. The installer is an executable named either setup-x86.exe or setup-x86_64.exe, and you’ll need it to add or remove Cygwin packages in the future. I suggest moving the installer to the same folder where you installed Cygwin itself; typically C:cygwin or C:cygwin64.

If you already have Cygwin installed, it’s a good idea to re-run the installer to make sure it has the latest available packages. Alternatively, you can install a new instance of Cygwin in a different folder.

2. Install Required Cygwin Packages

Next, you’ll need to add several packages to Cygwin. You can add them all in one fell swoop. Just open a Command Prompt (in Windows), navigate to the folder where the Cygwin installer is located, and run the following command:

C:cygwin64>setup-x86_64.exe -q -P wget -P gcc-g++ -P make -P diffutils -P libmpfr-devel -P libgmp-devel -P libmpc-devel

A window will pop up and download all the required packages along with their dependencies.

At this point, you now have a working GCC compiler on your system. It’s not the latest version of GCC; it’s whatever version the Cygwin maintainers chose as their system compiler. At the time of writing, that’s GCC 4.8.3. To get a more recent version of GCC, you’ll have to compile it yourself, using the GCC compiler you already have.

3. Download, Build and Install the Latest GCC

Open a Cygwin terminal, either from the Start menu or by running Cygwin.bat from the Cygwin installation folder.

If your machine is located behind a proxy server, you must run the following command from the Cygwin terminal before proceeding – otherwise, wget won’t work. This step is not needed if your machine is directly connected to the Internet.

export http_proxy=$HTTP_PROXY https_proxy=$HTTP_PROXY ftp_proxy=$HTTP_PROXY

To download and extract the latest GCC source code, enter the following commands in the Cygwin terminal. If you’re following this guide at a later date, there will surely be a more recent version of GCC available. I used 4.9.2, but you can use any version you like. Keep in mind, though, that it’s always best to have the latest Cygwin packages installed when building the latest GCC. Be patient with the tar command; it takes several minutes.

wget http://ftpmirror.gnu.org/gcc/gcc-4.9.2/gcc-4.9.2.tar.gz
tar xf gcc-4.9.2.tar.gz

That will create a subdirectory named gcc-4.9.2. Next, we’ll configure our GCC build. As the GCC documentation recommends, it’s best to configure and build GCC in another directory outside gcc-4.9.2, so that’s what we’ll do.

mkdir build-gcc
cd build-gcc
../gcc-4.9.2/configure --program-suffix=-4.9.2 --enable-languages=c,c++ --disable-bootstrap --disable-shared

Here’s a description of the command-line options passed to configure:

• The --program-suffix=-4.9.2 option means that once our new GCC is installed, we’ll run it as g++-4.9.2. This will make it easier for the new GCC compiler to coexist alongside the system GCC compiler provided by Cygwin.
• The --enable-languages=c,c++ option means that only the C and C++ compilers will be built. Compilers for other languages, such as Fortran, Java and Go, will be excluded. This will save compile time.
• The --disable-bootstrap option means that we only want to build the new compiler once. If we don’t specify --disable-bootstrap, the new compiler will be built three times, for testing and performance reasons. However, the system GCC compiler (4.8.3) provided by Cygwin is pretty recent, so --disable-bootstrap is good enough for our purposes. This will save a significant amount of compile time.
• The --disable-shared option means that we don’t want to build the new standard C++ runtime library as a DLL that’s shared with other C++ applications on the system. It’s totally possible to make C++ executables work with such DLLs, but it takes care not to introduce conflicts with C++ executables created by older or newer versions of GCC. That’s something distribution maintainers need to worry about; not us. Let’s just avoid the additional headache.
• By default, the new version of GCC will be installed to /usr/local in Cygwin’s virtual filesystem. This will make it easier to launch the new GCC since /usr/local/bin is already listed in Cygwin’s PATH environment variable. However, if you’re using an existing Cygwin installation, it might prove difficult to uninstall GCC from /usr/local later on (if you so choose), since that directory tends to contain files from several different packages. If you prefer to install the new GCC to a different directory, add the option --prefix=/path/to/directory to the above configure command.

We’re not going to build a new Binutils, which GCC relies on, because the existing Binutils provided by Cygwin is already quite recent. We’re also skipping a couple of packages, namely ISL and CLooG, which means that the new compiler won’t be able to use any of the Graphite loop optimizations.

Next, we’ll actually build the new GCC compiler suite, including C, C++, and the standard C++ library. This is the longest step.

The -j4 option lets the build process spawn up to four child processes in parallel. If your machine’s CPU has at least four hardware threads, this option makes the build process run significantly faster. The main downside is that it jumbles the output messages generated during the build process. If your CPU has even more hardware threads, you can specify a higher number with -j. For comparison, I tried various numbers on a Xeon-based machine having 12 hardware threads, and got the following build times:

Be warned: I encountered a segmentation fault the first time I ran with -j4. Bad luck on my part. If that happens to you, running the same command a second time should allow the build process to finish successfully. Also, when specifying higher numbers with -j, there are often strange error messages at the end of the build process involving “jobserver tokens”, but they’re harmless.

Once that’s finished, install the new compiler:

This installs several executables to /usr/local/bin; it installs the standard C++ library’s include files to /usr/local/include/c++/4.9.2; and it installs the static standard C++ library to /usr/local/lib, among other things. Interestingly, it does not install a new standard C library! The new compiler will continue to use the existing system C library that came with Cygwin.

If later, you decide to uninstall the new GCC compiler, you have several options:

• If you installed GCC to a directory other than /usr/local, and that directory contains no other files, you can simply delete that directory.
• If you installed GCC to /usr/local, and there are files from other packages mixed into the same directory tree, you can run the list_modifications.py script from this post to determine which files are safe to delete from /usr/local.
• You can simply uninstall Cygwin itself, by deleting the C:cygwin64 folder in Windows, along with its associated Start menu entry.

4. Test the New Compiler

All right, let’s compile some code that uses generic lambdas! Generic lambdas are part of the C++14 standard. They let you pass arguments to lambda functions as auto (or any templated type), like the one highlighted below. Create a file named test.cpp with the following contents:

#include <iostream>

int main()
{
    auto lambda = [](auto x){ return x; };
    std::cout << lambda("Hello generic lambda!n");
    return 0;
}

You can add files to your home directory in Cygwin using any Windows-based text editor; just save them to the folder C:cygwin64homeJeff (or similar) in Windows.

First, let’s see what happens when we try to compile it using the system GCC compiler provided by Cygwin:

g++ --version
g++ -std=c++1y test.cpp

If the system compiler version is less than 4.9, compilation will fail:

Now, let’s try it again using our freshly built GCC compiler. The new compiler is already configured to locate its include files in /usr/local/include/c++/4.9.2 and its static libraries in /usr/local/lib. All we need to do is run it:

g++-4.9.2 -std=c++14 test.cpp
./a.exe

It works!

https://preshing.com/20141108/how-to-install-the-latest-gcc-on-windows/