1.6: Preprocessing
- Page ID
- 40632
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Taking another step backward through the compilation process, you can use the -E
flag to run the preprocessor only:
$ gcc hello.c -E
The result is the output from the preprocessor. In this example, it contains the included code from stdio.h
, and all the files included from stdio.h
, and all the files included from those files, and so on. On my machine, the total is more than 800 lines of code. Since almost every C program includes stdio.h
, those 800 lines of code get compiled a lot. If, like many C programs, you also include stdlib.h
, the result is more than 1800 lines of code.