Make and GCC

Make

• Build automation tool
• Performs actions ordered by configured dependencies as defined in makefile

GCC

• GNU Compiler Collection
• Main compiler, linker, and assembler used for this class
• Free and open source optimizing compiler produced by the GNU project

What is GCC

• Just a program

> which gcc
/usr/bin/gcc

How to use GCC

• Run it
• Enter /usr/bin/gcc in the shell. If the location of gcc is in your PATH, you can simply type gcc and the OS will resolve the full path.

> gcc
gcc: fatal error: no input files
compilation terminated.

Compiling Files

Compile source files into executable

> gcc src1.c src2.c --output executable

Hello, world

hello.c:

#include <unistd.h>

int main() {
  write(0, "Hello, world!\n", 14);
  return 0;
}

Compile

Preprocess, compile, assemble, and link our program to the file hello

> gcc hello.c --output hello

Run

We now have a new executable file. We can run it in the shell as:

> ./hello

More advance operations

Compile source code into Assembler instructions:

> gcc -S src.c

Compile source code without linking:

> gcc -c src.c