C snippets and C FAQ🔗

1. Introduction
2. Bytes and char
3. Allocation
4. True or False
5. Strings
6. Sockets and network

I love C! It used to be one of the first language I have learnt when I was a child. Even if C is a very easy to learn language, it demands lots of practice to avoid common mistakes. If you are a daily C developper, you will be able to easily remember all of the tricks involved in practicing C.

As I can't be a daily C programmer, I keep this page in order to remember things I have discovered on this fascinating language. Some of them seem trivials but it doesn't harm to start from the basics.

• unsigned char is for bytes (raw data).
• char is for strings.

• It is not possible to grab the size of an allocated pointer with sizeof.
• You have to keep the length either a constant or in a dedicated variable.
• sizeof(array) will return the size in bytes for the array.
• use sizeof(array)/sizeof(array[0]) to find the number of elements of the array.
• Be careful with realloc: always ensure to use a pointer to a pointer as an argument for the function which will deal with reallocation. Otherwise, most of the time you will suffer with double free corruption because the reallocated pointer is local.

• True is non-zero!
• False is zero.

• In snprintf, the size argument does include the trailing (NULL) character.

• Don't use gethostbyname, use getaddrinfo instead. It does manage IPv6 much simpler than the previous libc version with gethostbyname.
• Read the good introduction on sockets on Beej's Guide to Network Programming.