Many people here rant about the dependency hell (rightly so). I'm doing systems programming for quite some time now and it changed my view on what I consider a dependency.
When you build an application you usually have a system you target and some libraries you use that you consider dependencies.
So the system is basically also a dependency (which is abstracted away in the best case by a framework).
What many people forget are standard libraries and runtimes. Things like strlen, memcpy and so on are not available on many smaller systems but you can provide implementations of them easily. Things like malloc are much harder to provide. On some system there is no heap where you could dynamically allocate from so you have to add some static memory to your application and mimic malloc allocating chunks from this static memory. Sometimes you have a heap but you need to acquire the rights to use it first. malloc doesn't provide an interface for this. It just takes it. So you have to acquire the rights and bring them magically to malloc without the actual application code noticing. So even using only the C standard library or the POSIX API can be a hard to satisfy dependency on some systems. Things like the C++ standard library or the Go runtime are often completely unavailable or only rudimentary.
For those of you aiming to write highly portable embedded applications please keep in mind:
- anything except the bare language features is a dependency
- require small and highly abstracted interfaces, e.g. instead of malloc require a pointer and a size to be given to you application instead of your application taking it
- document your ABI well because that's what many people are porting against (and it makes it easier to interface with other languages)

  • 3
    I just use static allocation. Not only that the linker tells whether there's a memory problem, it also avoids memory fragmentation because there's no MMU and the smallish physical address space is also the logical one.
  • 1
    Great post mate. It is awesome to be reminded of the fact that any code we write has to depend on something.
Add Comment