Thanks Glynn for let me know that the void* pointer arithmetic is
undefined, and gcc automatically cast it to char* pointer... is this
because void* doesn't have a size? im curious when i do sizeof(void*),
my machine tell me sizeof(void*) is 4kb... i thnk when i do (void* +
1) that's means "4 kb after void*"?....
i run the code in GNOME terminal, that's means stdout connected to xterm?
On Thu, Sep 10, 2009 at 7:46 AM, Glynn Clements
<glynn@xxxxxxxxxxxxxxxxxx> wrote:
>
> Randi Botse wrote:
>
>> void *buffer; /* buffer, will be allocated */
>> ...
>
>> ret = read(fdp, buffer + bytes, stat.st_size - bytes);
>
> Pointer arithmetic on a void* is undefined. gcc allows this as an
> extension, treating void* like char*, i.e. p+i is treated as
> (void*)((char*)p+i).
>
> For portability, define buffer as a char*.
>
>> printf("\rcompleted: %i%%", progress); /* NO OUTPUT, UNTIL LOOP ENDED */
>> fflush(stdout);
>
>> Then i see printf() never output the message until the loop has ended...
>> 'fdp' is a file descriptor to a local file, i send it through a serial
>> connection (RS232),
>
> Try checking the return value of printf() and fflush(), and errno upon
> error.
>
> Also, what is stdout connected to? A VT? An xterm? sshd?
>
> --
> Glynn Clements <glynn@xxxxxxxxxxxxxxxxxx>
>
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