Conventions

General conventions that C code should obey.

Memory allocation

Always check the return value of malloc. If it is a null pointer, derefence it to immediately abort the processas as we cannot reasonable recover from OOM in most cases. If such a recovery is possible, recover instead. On some platforms, dereferencing a null pointer does not abort the process. In these cases, the null pointer is a perfectly fine pointer, and just continue using it instead. Note that this derefence should usually be a volatile operation as the compiler would optimize it away otherwise. I have reported upstream issues on compilers about this, but they have not yet answered.

If the pointer is non-null, free it directly after the malloc call. This prevents memory leaks of all sorts. Afterwards, you can use it freely in your program.

Includes

#include directives shall be placed at the start of the file. But usually, it's better to not use the preprocessor at all. Paste the code in by hand so that it is clearly visible in version control.