4 layer reference model for communication error

I'm trying to simulate a simple 4 layer reference model for communication between two hosts. However, I seem to be getting a simple error, which I can't figure out.

The Part of my code is:

Code:

int* layer2(int* buf,int* bufsize, int flag)
{
	if(flag == 1) //Transmit
	{
		int packetnum = 1;
		
		if(bufsize[0] > MAXDATA)
		{
			double x = (((double)bufsize[0])/MAXDATA);
			packetnum = ceil(x);
		}

And the following error I'm getting refers to packetnum = ceil(x);

[Warning] converting to `int' from `double'

That's not an error; it's a warning. It's only letting you know that you're going to lose precision converting from double to int. If that's actually what you want to do, do a typecast.

In your program,you're trying to assign the double value to integer.That's why,it is giving warning.
To avoid this,we need to explicitly do type conversion.

In the case of operations,C itself manage it.For ex,if you're adding two integers and storing it in the double value,then the result will be implicitly converted to double value.

I tried your sample code with my sample inputs. It doesn't give any error or warning.
Normally C will handle this automatic type conversion. ( double to int )

Code:

#include<stdio.h>
#include<math.h>

int* layer2(int* buf,int* bufsize, int flag)
{
        if(flag == 1) //Transmit
        {
                int packetnum = 1;

                if(bufsize[0] > 10)
                {
                        double x = (((double)bufsize[0])/10);
                        packetnum = ceil(x);
                        printf("packet:%d",packetnum);
                }
        }
}

int main()
{

        int buf[]={1,2,3};
        int bufsize[]={25,30,40};
        layer2(buf,bufsize,1);
        return 0;
}