__rt_lib_init()

where:

This is the library initialization function. It is called immediately after __rt_stackheap_init() and passed an initial chunk of memory to use as a heap. This function is the standard ARM library initialization function and must not be re‑implemented.

The function returns argc and argv ready to be passed to main(). The structure is returned in the registers as:

struct __argc_argv
{
    int argc;
    char **argv;
    int r2, r3;
};