learn c

Examples of hello world C programs, libraries, headers and details of how to compile, link, and run from scratch (without using a build system like Make, cmake, or gyp).

Requires

• clang compiler

Usage

To build all examples:

./build-all.sh

To test all examples:

./test-all.sh

To build and test a specific example:

cd step_1
./build.sh
./test.sh

To build and test a specific example without causing your working directory to change:

(cd step_1 && ./build.sh && ./test.sh)

definitions

compiler

Command line tool, like gcc or clang, that can compile and link code

C compilers are gcc and clang. C++ compilers are g++ and clang++.

linker

The linker is usually called ld. But you don't need to invoke it directly. Instead it gets invoked by the compiler.

compile

Turn C or C++ code into .o (object files)

link

Turn object files into either and executable or a library

Build system

Not going to find one here! Actually that is a lie. Here we use bash scripts called build.sh to invoke the compiler to compile and link. For larger projects you'll want to use a build system like cmake, ninja, make, or gyp that is able to intelligently recompile and link only when certain files have changed.

Extra handy tools

• nm shows symbols (aka functions/methods) inside a library
• otool -L shows what dynamic a program links to on OS X
• ldd shows what dynamic a program links to on linux
• readelf -d shows rpaths and other special things about a library on linux