RS232 printf

[info@ckmintech.com]

I have problem to send a long integer or float number to a PC through RS232

printf("Output=%ld",123456);

The data received by the Hyperterminal is

Output=-5046

It's fine to send unsigned integer ans string.

Thanks

[rwyoung]

[Ttelmah]

The problem here, is that the 'L' specifier, has two meanings, according to the 'type' of the value being received. So if you give a 16bit value to it, it uses 16bit arithmetic, while if you give it a 32bit value, it switches 'up' again, and uses 32bit arthmetic. Unfortunately, using a constant (even though too large to fit into an int16), sometimes only results in the int16 behaviour, and you therefore overflow.
Now I am assuming that the code given is only a demo, otherwise there is no point at all in using such a constant inside a printf. What you need to do, is to ensure that the value received by the printf routine, is stored in a signed int32 variable, or cast into such a type.
You should find that:

printf("Output=%ld",(signed int32)(123456));

If you are using a variable to 'feed'the routine, you need to verify that these are signed int32 values, and also whn perfoming earlier arithmetic, be very careful about the type casting. For instance: