how_i_program_in_c_by_Eskil_Steenberg

• In the beginning you always want results, in the end you always want control. The bad reasons to use c are good reasons to use c.
• See what you can do with the tools/resources you have rather then how to make xyz.
• memory leaks are not difficult to solve once you get the hang of it.
• use C89 for futureproof code.
• readability is king, you spend more time reading your code then the compiler does.
• stupid is smart.
• have long variable names (and function names)
• crashes are good: any errors need to crash early and as loud as possible. see the ;
• Some definitions:
  • MY_DEFINE
  • MyType
  • my_function()
  • my_variable
• spacing is super important, consider searching.
• reuse names
  • array := arrays
  • type := enu
  • node := links to other node
  • entity := generic networked thing
  • handle := pointer to opaque data structure
  • func := function pointer
  • internal := function internal to a module
  • i,j,k := indexes for for loop
  • count := unsigned int
  • f := float
  • vec := vector
  • length
  • found := binary for an existence of something
  • next :~ loosely-defined
  • previous :~ losely-defined
  • list
• long functions that are sequential, not needing to jump between functions and files etc. is good.
• write function names in this form:
  • module_object_subject(); // this allows for all module functions to be seen, as well as all the functions regarding the object
• modular programming in c is good
• interface with headerfiles, don’t make one header file for every c file, instead make a master external headerfile for the folder as well as internal headerfiles
• You can do oop in c, in fact it is more realistic to what happens.
• void pointers are like encapsulation
• macros make it easy to shoot yourself in the foot, only do it when it is most sensible.
  • for debugging, especially memory leaks, to review, and for packing data.
  • FILE
  • LINE

Memory

• If something exists, it exists somewhere.
• memory :~ a very big array of bytes. (there is more to this, so see [[#memory cont]])
• pointer :~ an integer referencing a byte.
• datatype of a pointer matters.:
  • void *p;
  • short short_pointer = *p; // returns something 4 bytes long
  • int int_pointer = *p // returns something 8 bytes long
  • short_pointer++; // adds 2 bytes = sizeof(short)
  • int_pointer++; // adds 4 bytes = sizeof(int)
• sizeof is a cast, not a function:
  • double *a;
  • a = malloc( (sizeof *a) ); is way better then
  • a = malloc( sizeof(float) ) note, this is typecasting
• pointers and arrays are the same thing
• you can use pointers as counters.
• uint i;
• for(i=0;i < 10;i++)
• p[i] = 0
• is actually doing a multiplication under the hood, which is, p + (sizeof *p) * i

structs

• Structs:~ a sizeof and a bunch of offset types
• Alignment will make things complicated
• data needs to be stored on even numbers, the ordering matters. The compiler does this to be faster
  • typedef struct{
  • uint32 a;
  • uint8 b; } this will take up 8 bytes. Size allocated will always be multiples of 4

memory cont

• Each 4k block has read/write/execute flags
• block addresses are virtualised
• realloc()
• watch out for this infamous bug:
  • when you use an array beyond where it is supposed to be, it will still read/write as long as it is not beyond the current memory block!
    • {
    • uint a[10],i;
    • for (i = 0; i < 11; i++)
    • a[i] = 0;
    • }
  • there is a windows application called gflags, which shows the bugs of this kind!
• memory is ridiculously slow, and math is ridiculously fast!
• linked lists are terrible for optimisation
  • realloc:
• bad
• typedef struct{
• float width;
• float length;
• float area;
• }
• use setters and getters
• TODO slide 37
• stride :~ tells how big a piece of memory
• stride allows for versitile functions.
• Architecture :~ how to structure code, how to design it all.
• pick primitives, such as tringles only for graphics.
• Code a mountain.
• an application should be small, like a house. Build a small house on a mountain
• You should not be afraid of writing code!
• Code you own doesn’t age.
• Fix it now:
  • If you know your code should be different fix it now.
  • Don’t wait
  • it won’t be easier in the future
  • no you won’t get more time to do it later
  • no it won’t take too much time
  • you will earn it back faster then you think
• you can use pointers as unique … TODO
• contact info see his video

c

backlinks

• index_of_files.pd