I know that fwrite takes the following parameters:
fwrite ( const void * ptr, size_t size, size_t count, FILE * stream );
As far as I know, size_t is a typedef and nothing else than:
typedef unsigned long size_t;
Is it possible to use values greater than size_t for count and write?
And if it is not could I connect the written blocks somehow?
From an application programmers point of view a file is a contiguous series of bytes. Successive writes will position the data sequentially onto a file. (This comment is necessary because some will argue details NOT relevant to your question).
Thus:
fwrite(&user_record1, sizeof(user_record1), 1, fp);
fwrite(&user_record2, sizeof(user_record2), 1, fp);
Results in two user records, one immediately following the other, on the file.
If you have a very large record, then divide it into two smaller records, as:
fwrite(&user_record_parta, sizeof(user_record1), 1, fp);
fwrite(&user_record_partb, sizeof(user_record2), 1, fp);
However, I would question an application design that uses such large records. Perhaps what you are really doing in the application is writing an array of user records and that array grows really large. If this is the case, write each entry of the array, rather than the whole array.