c - Copy a list to a binary file -

i'm trying copy contents of struct in list binary file.

here's structures declarations:

typedef struct {     char dni[9];     char nombre[100], apellido[100];     double deuda; } t_datos;  struct s_nodo {     t_datos dati;     struct s_nodo *sig; }; typedef struct s_nodo *t_nodo; void newfile(t_nodo, file *); 

in main fill list data .dat file , , looks ok, because if print list ok.i've got problem when try copy struct i've in list new binary file.

//open , copy old binary file list... fc = fopen("c:\\norep.dat", "w+b"); if (fc == null) {     puts("error");     exit(-1); } newfile(lista, fc); 

here's function:

void newfile(t_nodo lista, file *fc) {     if (lista != null)      {         fwrite(lista->dati, sizeof(t_datos), 1, fc);         newfile(lista->sig, fc);     } } 

the error is:

error: incompatible type argument 1 of 'fwrite'|

i know mistake in way i'm passing list function, saw prototype of fwrite don't know how should fix code.

the first argument of fwrite() must pointer (const void * to precise), in case it's not. have use & address of operator, this

fwrite(&lista->dati, sizeof(lista->dati), 1, fc); 

also, might want check return value of fwrite() sure succeeded, in case since writing single item has 1.

warning: don't typedef poitners, might problem in future. , if must, use kind of notation suffix _ptr indicate it's pointer (libxml-2.0 uses ptr example).