4 Tips For Faster C++ Compilation Times:
This post is about some techniques I have used to improve compilation times. This might be useful to you, if your compile times are long. In this post, I will talk about some techniques and tools that I use to reduce C++ compile time on Linux, including ccache and distcc.
(Note: Compiling is the process of translating a program written in a high-level language like C or C++ into the machine language that computer understands.)
I have an 8 core computer with 16GB RAM. When I started programming in C++, it took ages for me to compile my code. I was so frustrated with the compilation times that I actually timed it up once. It took around 8 minutes for just compiling my code! Since then, I found several ways to reduce C++ compilation time and now my code compiles in less than 5 seconds. If you think that’s cool, read on!
Why You Need Faster Compile Times?
One of the most common complaints about C++ is its slow compilation times. The problem is that C++ is a statically typed language, which means the compiler needs to know about every variable and type before it can compile the program. This makes it impossible for the compiler to convert code into binary as fast as Python, for example.
However, by changing your coding style and using some tips and tricks along the way you can significantly reduce compilation times in C++. I’ve compiled 4 tips that should help with this issue in your projects:
1. Use forward declarations.
2. Avoid unnecessary
C++ is a statically typed language that requires each variable to be declared before it can be used. In contrast, dynamically typed languages like Python do not need variables to be declared, and thus compile much faster.
This is the primary reason why C++ compilations are slower than Python or Java. But there are numerous other reasons as well. In this article, we will discuss 4 ways to speed up your C++ compilation times.
1. Compile Single Source File at a Time
2. Precompiled Header Files
3. Use Distcc for Distributed Compiling
4. Profiling Your Builds
As a C++ programmer, we spend most of the time compiling the source code at all times. You might have come across these situations where you wish for your compiler to compile faster. In this article, we will see how to speed up the compilation time.
There are two different methods that can be used to speed up compilation times: 1) Paralleling and 2) caching.
Compiling in parallel is one of the easiest and important ways to decrease compilation time. We need to make sure that we use some build tools like make, cmake, ninja or distcc that support parallelization. For example, if you are working on a multicore machine with 4 cores, adding -j4 in case of make or -j8 in case of ninja can speed up the compilation significantly.
One thing we need to consider while parallelizing is that the build server should have enough memory (RAM) since more processors will mean more RAM usage.
Caching Compilation Results
Caching compilation results can also be useful for speeding up compilation times by avoiding recompilation of files which did not change or were already compiled before. There are many different tools like ccache which can help us cache our compilation results. It is advisable to add c
The compilation of a large project usually takes several minutes or even more than an hour on a large scale project. A 3-minute compilation time is enough to get distracted and go for a cup of coffee.
If you are tired of waiting for your C++ program to compile, then here are some tips that can possibly speed up the compilation process.
1. Use precompiled headers. 
Precompiled headers in C++ are used to speed up the build process or compilation process by saving the state of the code being compiled to a file, so that it can be reused in future compilations without having to recompile it all again. This technique is very useful when you include standard library files such as ”
When you compile a program and invoke the linker, you may have to wait for quite some time depending upon the size of the project. C++ is a compiled language and even a slight change in any header file will cause the entire project to be re-compiled.
Over the years, we have been working on improving our compilation times at Programiz. With each new feature, we are faced with slow compilation times. Here are some techniques that I use personally to improve our compilation and build times.
Compile only what is required
When your program has more than one source code files (Classes, functions), it’s not necessary to recompile all files when there is any change in one of them. So, whenever you have to make changes to a particular file say foo(), always check the dependencies before compiling your program or rebuilding your project.
If you are using make utility or writing Makefile then run:
make -n foo
to see what commands would be executed and what files will be compiled if you were to compile ‘foo’. This way, you can analyze which files need to be recompiled. You can also use this tip to identify unnecessary dependencies as well. If you are using a GUI IDE like Visual Studio or XCode then they
I was working on a C++ project which took over 6 minutes to compile. That is just too much time, so I decided to optimize it. After a lot of research and experimenting, I managed to cut the compilation time by 45%. This blog post will show you how you can do the same thing.
Let’s get started!
Split your project into multiple modules
A module is simply a collection of related functions. For example, if you have a program that uses only two functions one for printing “Hello World” and another for adding two numbers, then you can split this into two modules: one for printing and another for addition. This way, when you change the code in either of these modules, the compiler will not need to recompile the other module.
For splitting your project into modules, make sure that each module depends on as few header files as possible. If a header file contains function declarations that are used by more than one module, consider splitting it up into multiple header files – each containing only those declarations that are required by a single module.
Include header files in .cpp instead of .h
The C++ compiler has to process all includes before compiling the code in the file itself (this step is called preprocessing). This means