Is there any way to print all nested struct size in C?-CodePudding

I have a case where there are multiple structures contained in one structure. Small example:

typedef struct data {
     int x;
} data_t;

typedef struct info {
    data_t data_element[10];
    int y;
} info_t

Is there any way to print all struct sizes which are members of info_t?

CodePudding user response：

Not without knowing what those types are. C does not have reflection (the way that java or c# do, for example).

If you do know the types it's simply a matter of using sizeof and a print function.

CodePudding user response：

This is impossible using the C language alone, since it does not provide for such introspection. All you can do is iterate over the struct members and print their sizes.

That said, a decade ago, I had to do just this for large complicated struct of several hundred members. I finally got the required information from parsing the debugging section of the object file. I don't have details anymore, but you will need to compile with the -g flag and then dump debug output with an appropriate tool. Try looking at the readelf and objdump utilities and manual pages.