Makefile

all: sorted_list.exe

sorted_list.exe: sorted_list.c sorted_list.h
	gcc sorted_list.c -o sorted_list.exe

sorted_list.c

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "sorted_list.h"

SortedList *sorted_list_new(void *base, size_t num, size_t size, 
							int (*compare)(const void *, const void *))
{
	SortedList *sl;
	Element *e;
	unsigned int e_num;

	sl = malloc(sizeof(SortedList));
	e = malloc(num * sizeof(Element));

	qsort(base, num, size, compare);
	e[0].prev = NULL;
	e[0].data = base;
	
	for(e_num = 1;e_num < num;e_num++)
	{
		e[e_num - 1].next = &e[e_num];
		e[e_num].prev = &e[e_num -1];
		e[e_num].data = base + e_num * size;
	}

	sl->head = &e[0];
	sl->tail = &e[num - 1];
	sl->length = num;
	sl->size = size;
	return sl;
}

void sorted_list_merge(SortedList *a, SortedList *b)
{
	SortedList *temp;
	Element *pos_a, *pos_b;
	if(a->length > b->length)
	{
		temp = a;
		a = b;
		b = temp;
	}
	if(a->length == 0)
	{
		a = b;
	}
	else
	{
		pos_a = a->head;
		pos_b = b->tail;
		while(pos_a != NULL && pos_b != NULL)
		{
			
		}
	}
}

void *sorted_list_to_array(SortedList *sl)
{
	void *array;
	Element *e;
	unsigned int e_num;
	array = malloc(sl->length * sl->size);
	e = sl->head;
	for(e_num = 0;e_num<sl->length;e_num++)
	{
		memcpy(array + e_num * sl->size, e->data, sl->size);
		e = e->next;
	}
	return array;			
}

int cmp(double *a, double *b)
{
	if(*a > *b) return 1;
	if(*a == *b) return 0;
	return -1;
}

int main(int argc, char **argv)
{
	int arg, pos;
	double **list;
	size_t *length;
	size_t n; 
	if(argc < 2)
	{
		return 0;
	}
    
	list = NULL;
	length = NULL;
	n = 0;
	for(arg = 1;arg < argc;arg++)
	{
		printf("%d: %s\n", arg, argv[arg]);
		if(argv[arg] > 0)
		{
			n++;
			length = realloc(length, n * sizeof(size_t));
			length[n - 1] = atoi(argv[arg]);
			
			list = realloc(list, n * sizeof(double *));

			list[n - 1] = malloc(length[n - 1] * sizeof(double));

			for(pos = 0;pos < length[n - 1];pos ++)
			{
				list[n - 1][pos] = atof(argv[arg + pos + 1]);
			}
			arg += length[n - 1];
		}
		SortedList *sl = sorted_list_new(list[n-1], length[n-1], sizeof(double), (int (*)(const void *, const void *))cmp);
		double *arr = (double *)sorted_list_to_array(sl);
		int i;
		for(i=0;i < sl->length;i++) printf("%.3f  ", arr[i]);
		printf("\n");
	}
	
	return 0;
}

sorted_list.h

typedef struct _Element Element;
typedef struct _SortedList SortedList;
struct _SortedList
{
	Element *head;
	Element *tail;
	unsigned int length;
	size_t size;

	int (*compare)(const void *, const void *);
};

struct _Element
{
	Element *next;
	Element *prev;
	void *data;
};