initialize pointer in main and reserve memory in different function

Hello,

in my main function I initialize a char pointer. This pointer I overgive a function setMemory(char **ptr) as a parameter where some memory shall be allocated. Additionally some data shall be stored in this function. Back in main function I try to read out the data to which the pointer shows, but no data were outputted. Why?

Additionally I implement a short example as a console application in C and all is working. Maybe the issue is msp430 depending?!

The example code is the following:

#include <msp430.h> 

/*
 * main.c
 */

#include "testfile.h"
#include "stdio.h"

int main(void) {
    WDTCTL = WDTPW | WDTHOLD;	// Stop watchdog timer
	setvbuf(stdout, NULL, _IONBF, 0); 			// turn off buffering for stdout
	char *testPointer;

	testFunktion(&testPointer);
	printf("String: %s", testPointer);
	while(1);
	
	return 0;
}

//new c-file with testFunction inside

void testFunktion(char **testPointer){
	*testPointer = (char*)malloc(sizeof(char)*2048);
	(*testPointer)[0] = 'c';
	(*testPointer)[1] = '\0';
	printf("StringFunktion: %s\n", *testPointer);
}

printf prints only the string, not data of the pointer.