#include <stdio.h>
#include <stdlib.h>

typedef struct tableEntry {unsigned int nr; int p; float z;} T_ENTRY;

int readFile(char* filename, T_ENTRY *tableEntries);
void printTable(int n, T_ENTRY *tableEntries);

int main(void) 
{
	T_ENTRY *tableEntries; <<<<<< anlegen des pointers
	int n;
	
	n = readFile("daten.dat", tableEntries); <<<<< aufruf
		
[...]

int readFile(char *filename, T_ENTRY *tableEntries)
{
	FILE *filePointer;
	int i, n;
	
	filePointer = fopen(filename, "r");
	
	fread(&n,sizeof(int),1,filePointer);
	
	tableEntries = malloc (sizeof (T_ENTRY) * n); <<<<< neue adresse, die nicht zurückgeschrieben wird
	
[...]