STM32F105, arm-none-eabi-gcc, Contiki: Storing float in struct and printing float in C fails - struct

Question

I have two typedef struct as shown below:
typedef struct{
UInt32 length;
void* data;
UInt16 value;
} my_type;
typedef struct{
UInt8 type;
UInt32 length;
void* value;
} tlv_t;
What I trying next is to allocate memory for an my_type struct, a tlv_t struct that is pointed to from the created my_type object and for a float number, which is pointed to from the tlv_t object.If I'm executing the code without the last line of the code below it is working well. I can store the value and I can access it.But as soon as I try to access it a second time the uploaded code isn't running at all anymore on the STM32F105 Contiki-based board. The odd part is that this is only the case when using floating point numbers. No problems at all with other datatypes like int. Unfortunately, I really need to use float... What am I doing wrong?
Another problem is that printf doesn't support some flags like %f or %ul. Does anybody know how to add support for it on Contiki?
my_type* t = malloc(sizeof(my_type));
t->data = malloc(sizeof(tlv_t));
tlv_t* tv = t->data;
tv->type = 10;
tv->length = sizeof(float);
tv->value = malloc(sizeof(float));
*(float*) tv->value = 212.32;
printf("tv->value: %i\n", (int) *(float*) tv->value);
printf("tv->value: %i\n", (int) *(float*) tv->value); // without this line it is working
EDIT:
I forgot to add these typedefs:
typedef unsigned char UInt8;
typedef unsigned short UInt16;
typedef unsigned long UInt32;
EDIT2:
Here is the complete code:
#include <contiki.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <cfs/cfs.h>
#include <cfs/cfs-coffee.h>
#include "arg.h"
/*---------------------------------------------------------------------------*/
PROCESS(main_process, "Contiki CLV build015_1");
AUTOSTART_PROCESSES(&main_process);
/*---------------------------------------------------------------------------*/
PROCESS_THREAD(main_process, ev, data)
{
PROCESS_BEGIN();
my_type* t = malloc(sizeof(my_type));
t->data = malloc(sizeof(tlv_t));
tlv_t* tv = t->data;
tv->type = 10;
tv->length = sizeof(float);
tv->value = malloc(sizeof(float));
*(float*) tv->value = 212.32;
printf("tv->value: %i\n", (int) *(float*) tv->value);
printf("tv->value: %i\n", (int) *(float*) tv->value); // without this line it is working
while (1) {
PROCESS_YIELD();
}
PROCESS_END();
}
EDIT3:
I'm using the latest arm-none-eabi-gcc (version 4_8-2013q4-20131204). Are there any known issues when dealing with structs, floats or memory management?

Answer 1

Try
PROCESS_THREAD(main_process, ev, data)
{
static my_type *t;
static tlv_t *tv;
static float f = 212.32;
PROCESS_BEGIN();
t = (my_type *)malloc(sizeof(my_type));
t->data = malloc(sizeof(tlv_t));
tv = (tlv_t *)t->data;
tv->type = 10;
tv->length = sizeof(float);
tv->value = malloc(sizeof(float));
//*(float *) tv->value = 212.32;
memmove(tv->value, &f, 4);
printf("tv->value: %i\n", (int) *(float*) tv->value);
printf("tv->value: %i\n", (int) *(float*) tv->value); // without this line it is working
printf("t address: %x \n", (unsigned int)t);
while (1) {
PROCESS_YIELD();
}
PROCESS_END();
}

Answer 2

I suggest you fix your code, so you get no compiler warnings anymore (don't turn them off). Add casts as needed.
After I did those fixes your code worked for me, so the code is ugly but ok.
#define UInt32 unsigned int
#define UInt16 unsigned short
#define UInt8 unsigned char
typedef struct{
UInt32 length;
void* data;
UInt16 value;
} my_type;
typedef struct{
UInt8 type;
UInt32 length;
void* value;
} tlv_t;
int _tmain(int argc, _TCHAR* argv[])
{
my_type* t = (my_type*)malloc(sizeof(my_type));
t->data = malloc(sizeof(tlv_t));
tlv_t* tv = (tlv_t*)t->data;
tv->type = 10;
tv->length = sizeof(float);
tv->value = malloc(sizeof(float));
*(float*) tv->value = (float)212.32;
printf("tv->value: %i\n", (int) *(float*) tv->value);
printf("tv->value: %i\n", (int) *(float*) tv->value); // without this line it
getchar();
}
gives
tv->value: 212
tv->value: 212