Sprintf error - Codewarrior 8.1.1a

[v_dave]

Hello All,

I have a bit of a strange one here and I just can't seem to find a solution.  I use sprintf() to format strings which I then send out a SCI port a little later.  My problem is one particular string that I build has an incorrect number in it after sprintf() is complete.

typedef struct MOT_PARAM{...unsigned int BaudRate;  //Baudrate setting between Main and Interface PCB...}mot_param;mot_param UA_Param;unsigned char debug_buf[64];size = sprintf((char *)debug_buf, "SB%d\r", (unsigned)UA_Param.BaudRate);

So here is the issue:

if UA_Param.BaudRate = 4800 or 9600 or 19200 then he string created is always correct i.e.

SB4800\r

SB9600\r

SB19200\r

However when UA_Param.BaudRate is greater than 19200 (such as 38400, 57600 & 115200) then the output string has the negative value of the Baudrate i.e.

So if UA_Param.BaudRate = 38400 i get SB-27136\r but it should be SB38400\r

What I cannot figure out is why any number larger than 19200 is being converted incorrectly.  Does anyone have any ideas?

Details:

Target CPU - DSC56F8323

Codewarrior 8.1.1a for the DSC56F8000E

My Desktop OS - Win XP SP3

Thanks in advance for any help.

[kef]

Printf conversion type character 'd' is for signed integers. 'u' - for unsigned. You should change %d to %u.

Printf has no way to check what you are pushing to the stack in parameter list. Printf uses format string as a declaration what are you passing to it.

[bigmac · Accepted solution]

Hello,

Additionally, a value of 115200 would exceed the bounds of an unsigned int, and would require a long integer to handle.  Another approach would be to handle the value as 96, 192, 384 .. 1152, and add the final two zeros as ASCII characters.

Maybe  "SB%u00\r",

Regards,

Mac

[v_dave]

Hello All,

Thanks for the help.  I found bigmac's solution to be the best.  I had one of those "duh" moments when he reminded me that 115200 is to big for an unsigned integer. 

I already recieve the baud rate in as an ASCII string via the serial port so I have simply dropped the '0' off the end then I do an atoi() and this solved the problem.  When I report the data back out the suggested "SB%u00\r" is perefect.

Thanks again.

[Lundin]

Or simply save the baudrates as strings  

It will mean an immense saving of flash memory. Am I nuts? No... because if they were saved as strings in the first place, you wouldn't need the horrible sprintf() function, nor would you need your own less horrible int-to-string function.