#include <stdio.h>

#define MIN_BUFFER	1		/* 1 Byte */
#define MAX_BUFFER	4 * 1024	/* 4K */
#define FILE_SIZE	32 * 1024	/* 32K */

int main()
{
	int i, c;
	FILE *file;
	char buf[MAX_BUFFER];
	long tbegin, tend;

	if ((file = tmpfile()) == NULL)
		return 0;
	for (c = 0; c < MAX_BUFFER; c++)
		buf[c] = rand();
	i = 0;
	while (i < FILE_SIZE)
	{
		tbegin = clock();

		if (i + c > MAX_BUFFER)
			c = MAX_BUFFER - i;
 
		fwrite(buf, 1, c, file);
		i+= c;
		tend = clock();
		printf("%4d: read %d\n", c, tend - tbegin);
	}

	fclose(file);
	return 0;
}