Sort an array of struct(ure)s using standard c library functions?

See more:

C++

C

I have an array of structures, each of this type

struct A {
char filename[];
off_t filesize;
};

I'm trying to sort this array of structs according to filesize, so that I can , for instance, print the 5 largest file (include filename and its size) from this array of data.


Also I'm trying to avoid manually write up bubble sort or whatever algorithm. So are there any functions from standard c libraries that I can grab?