In this step, our object code code.o is linked with the other code we are using. The command to generate object code is: gcc -c code.cĪ section of the contents of the code.o file is: 7f45 4c46 0201 0100 0000 0000 0000 0000 The assembler takes our assembly code code.s and converts it in object code code.o. ident 'GCC: (GNU) 4.8.5 20150623 (Red Hat is an interesting and insightful piece of code which you should go through so that you will get the idea of how our C code and header files have been converted to such a short and optimized code. The contents of the assembly code will be as follows. The command to generate the assembly code is: gcc -S code.c The assembly code is the code written in assembly language. The compiler will convert the preprocessed code code.i into assembly code code.s. Following is a small section of the output for us to analyze: # 1 'code.c'Įxtern int ftrylockfile (FILE *_stream) _attribute_ ((_nothrow_, _leaf_)) Įxtern void funlockfile (FILE *_stream) _attribute_ ((_nothrow_, _leaf_)) Īs you will see the resulted code that is the main function can been reduced to only the statements that are executed and the code has been removed as well. The output is huge due to the contents of the stdio.h file.

The command to see the preprocessed code is: gcc -E code.c keep only the code defined as per the include guards (ifndef in our case).replace the include header files statements with the actual content of the header file.In this preprocessor step, we do the following: If we simply compile and execute the code, we will get the expected output.

In our example code, we will add a custom header file and use include guards ifndef so that we can understand the process completely. We will go through all the four steps in detail through an example C code to clarify the ideas involved. Gcc code.c # generates linked object code In summary, the commands are: gcc -E code.c # generates preprocessed code The different steps involved in compiling a C code are: We will explore the compilation steps in C. In this process, the code goes through different steps depending upon the compiler and language.

Reading time: 20 minutes | Coding time: 10 minutesĬompilation is the process of converting a code in a programming language (C in our case) to machine code.

Compiling code