easy way to display the contents of data structures in C ?

Question

For debugging purposes, I find it useful to display the contents of data structures. (In Python for example, I would just do "print some_dict_name").

Can this be achieved in C this easy too by using a standard library, or do I have to implement this myself depending on the data structure ?

Consider the following code, where I have to iterate over the StructArray again to display all of its contents.

#include <stdio.h>

struct SomeStruct {
  int id;
  };

int main() {
  struct SomeStruct StructArray[10];
  int x = 0;

  for (x = 0; x < 10; x++) {
    StructArray[x].id = x; 
  }

  for (x = 0; x < 10; x++) {
    printf("StructArray[%d].id = %d\n", x, StructArray[x].id);
  }
  return 0;
}

Answer 1

You need to implement it yourself per data type.
C doesn't have a type system where you can dynamically or statically visit each part of each type.

If you are live-debugging with something like gdb though, its inteligent enough to read debugging info and print type contents. But you can't do that from the program itself, there is no such a thing as introspection for C types.

Answer 2

A really hackish way would be compiling your program with debug information, and build a debugging library into the program to read the debugging information from the program itself in runtime. Parse what should be parsed from it, and print the struct accordingly.

That's a project on its own though.

Answer 3

Or, you could use something like DDD, the Data Display Debugger.