在多个结构指针和数组中将值分配给结构指针的成员

Question

long title. but it is the exact problem i am having. it may be a misunderstanding of how the struct pointer works, or a problem using tthe correct format. i have the following typedefs of structs combined in a big 'box' for easy passing around the configuration.

typedef struct NTC_network{
     unsigned char NET_ID;      
     unsigned char DEV_ADDR;        
}NTC_network;

typedef struct NTC_io_trx_link{
  enum NTC_IO_LINK own_io;
  unsigned char ADDR;
  enum NTC_IO_LINK trx_io;
}NTC_io_trx_link;

//struct to hold status of I/O. 0==OFF 1==ON
typedef struct NTC_config_stpio{
    unsigned char L1:1;
    unsigned char L2:1;
    unsigned char L3:1;
    unsigned char L4:1;
    unsigned char E1:1;
    unsigned char E2:1;
    unsigned char T1:1;
    unsigned char T2:1;
}NTC_config_stpio;

typedef struct NTC_header {
    unsigned char NET_ID;   
    unsigned char DST;      //destination address
    unsigned char SRC;      //source address
    unsigned char PCKT;             
}NTC_header;

typedef struct NTC_default_setup{
    unsigned char DEFAULT_SETUP:1;
}NTC_default_setup;    

typedef struct NTC_data{    
    unsigned char E1;       //resistor value to emulate on E1
    unsigned char E2;       //resistor value to emulate on E2
    unsigned char T1;       //resistor value of temperature sensor on T1
    unsigned char T2;       //resistor value of temperature sensor on T2
    unsigned char D1;       //230VAC detection circuit on/off
    unsigned char D2;       //230VAC detection circuit on/off       
    unsigned char ALRM;     //alarm on off 0xFF=alarm on, 0x00=alarm off            
}NTC_data;

typedef struct NTC_ack{
    unsigned char ACK;      //ACK field 0x00=no ack 0xFF= ack
}NTC_ack;

typedef struct NTC_config {
    NTC_default_setup *DEFAULT_STP;
    NTC_config_stpio *STPIO;
    NTC_config_network *NETWORK;
    NTC_io_trx_link *NTC_link_io;               
}NTC_config;

//struct for payload to send via LoRa
typedef struct NTC_payload{
    NTC_header *Header;
    enum NTC_dc DC; 
    NTC_config *Config;
    NTC_data *Data;
    NTC_ack *Ack;   
}NTC_payload;

typedef struct NTC_runtime_data{
    NTC_payload *pPayload;  
}NTC_runtime_data; 

and allocating the whole thing at runtime as such:

NTC_runtime_data* init_struct_runtime_data(void){   

    NTC_runtime_data *DATA = calloc(1, sizeof(NTC_runtime_data));   

    DATA->pPayload = calloc(2, sizeof(NTC_payload));
    for(int i = 0 ; i < 2; i++){
        DATA->pPayload[i].Header = calloc(1, sizeof(NTC_header));
        DATA->pPayload[i].DC = NONE; 
        DATA->pPayload[i].Config = calloc(1, sizeof(NTC_config));
        DATA->pPayload[i].Config->DEFAULT_STP = calloc(1, sizeof(NTC_default_setup));
        DATA->pPayload[i].Config->STPIO = calloc(1, sizeof(NTC_config_stpio));      
        DATA->pPayload[i].Config->NETWORK = calloc(1, sizeof(NTC_config_network));
        DATA->pPayload[i].Config->NETWORK->NTC_NETWORK = calloc(1, sizeof(NTC_network));
        DATA->pPayload[i].Config->NTC_link_io = calloc(11, sizeof(NTC_io_trx_link));
        for(int j = 0; j < 11; j++){
            DATA->pPayload[i].Config->NTC_link_io[j].own_io = j + 1;
        }           
        DATA->pPayload[i].Data = calloc(1, sizeof(NTC_data));
        DATA->pPayload[i].Ack = calloc(1, sizeof(NTC_ack));
    }
    return DATA;
}

i am allocating 2 pPayload. one for TX data and one for RX. all this works fine and there is no problem what so ever assigning values like so:

    NTC_runtime_data *pDATA;
    pDATA = init_struct_runtime_data();

and then where ever i might pass this struct i can assign as follows:

pData->pPayload[0].Header->NET_ID = 0x20;

but i am having problems with trying to assign from a struct containing an array as a buffer which looks like this:

typedef struct TRX_buffer{
    size_t used;
    size_t size;
    unsigned char *array;
}TRX_buffer;

and initializing and reallocating as so:

TRX_buffer* init_struct_trx_buffer(void){
    TRX_buffer *trx_buffer = malloc(sizeof(TRX_buffer));
    trx_buffer->array = malloc(4 * sizeof(unsigned char));
    trx_buffer->size = 4;
    trx_buffer->used = 0;
    return trx_buffer;
}
//inserts a byte of data in the buffer and dynamically allocates the buffer
void insert_array(TRX_buffer *trxbuffer, unsigned char data){
    if(trxbuffer->used == trxbuffer->size){
        trxbuffer->size *= 2;
        trxbuffer[0].array = realloc(trxbuffer[0].array, trxbuffer->size * sizeof(unsigned char));
    }
    trxbuffer[0].array[trxbuffer->used] = data;
    trxbuffer->used++;
}

so the problem is, some where in my program ,in a function, where i am creating a new instance of the buffer and load data from the radio, which i can see when debugging, i want to load it to my struct and i do it like this

NTC_payload* get_payload(NTC_payload *pPayload){    
    TRX_buffer *rx_buffer;
    rx_buffer = init_struct_trx_buffer();

    r_FIFO(rx_buffer);

    pDATA->pPayload[1].Header->NET_ID = trx_buffer->array[0];

the correct data is in the trx_buffer after my r_FIFO() function. but this isn't working. i have tried different methods. but cant get it to take the value from my buffer and assign it to my struct.

what is wrong??

Answer 1

You are not returning anything from init_struct_runtime_data(), so pDATA = init_struct_runtime_data(); gets whatever happened to be in the return register.

Any decent compiler should flag this, if yours doesn't do yourself a favour and uninstall it.

ps: there is a faq around here somewhere that talks about posting complete programs so people can try them with their tools. It is a good idea, because simply reducing the problem to a publishable version reveals the problem.