PRG2 setup

Reading complex expressions

When you start reading some code in libraries or for more complex projects than your labs, you'll start encountering complex expressions like here.

const char (*p)(double, float *);

How are you mentally reading that ? p is a pointer to a function taking a double and pointer to a float, this function returns a constant char.

There is a nice rule called the Clockwise/Spiral Rule sent by David Anderson on a Google Groups forum in 1994. You can see a formatted version here.

If you prefer to see a video, you can use another approach.

Interpreting Complex Declaration | How to read complex declaration in C / C++ ?

Accessing documentations

Man pages

The C documentation is mostly available through man pages, so having a nice colored manual display is important

# Add colors to man page ! Use bat as pager.
export MANPAGER="sh -c 'col -bx | bat -l man -p'"
export GROFF_NO_SGR=1

Here is the result

You can try other highlighting themes of bat, see the list in bat --list-themes and choose with --theme="theme name here".

This obviously requires bat: sudo dnf install bat.

Tips in VSCode

You can easily visit man pages with a few colors with this extension

code --install-extension meronz.manpages

The 3 useful actions:

1. (Only from shortcut) manpages.openFromCursor: With your cursor on a C function (let's say printf), run Ctrl+6 to open the printf man pages on a split page. This actually works any keyword that has a manual page, you can also use this on commands inside a given script.
2. (Accessible via Command Palette > Man: Open page) manpages.openFromInput: Same but opens a prompt to give the man page name
3. (Accessible via Command Palette > Man: Search (apropos)) manpages.searchFromInput: Same but opens a prompt to search across all man pages for a given keyword in name or short description

Here a snippet to insert in keybindings.json to quickly change the first shortcut to something else if you don't like the default ones.

{
    "key": "ctrl+shift+m",
    "command": "manpages.openFromCursor"
},

{
    "key": "ctrl+shift+m c",
    "command": "manpages.openFromCursor"
},
{
    "key": "ctrl+shift+m i",
    "command": "manpages.openFromInput"
},
{
    "key": "ctrl+shift+m s",
    "command": "manpages.searchFromInput"
},

Random tips

1. Binary files inspection: when working with binary files you might want to manually check the result or inspect the files to see exact bytes. For this, using xxd or hexdump (with -C or -c) works well !
2. Your tips ??

Did you found some errors or improvements ? Please contribute back by email (samuel.roland username for heig domain) or with a PR !