topic Re: I am having trouble with sprintf when using it with char... in Classic/Legacy CodeWarrior

I am having trouble with sprintf when using it with char...

bob_s — Tue, 28 Oct 2008 04:11:11 GMT

I am having trouble with sprintf when using it with char arrays instead of char pointers even when I use typecasting.

Example:
char tmpstr[16];

sprintf((char *)tmpstr, " %X", 1024);

I get a string with %X in it instead of 400.
I'm not a 'C' guru by any stretch.

Any ideas?
Thanks.
Bob

Re: I am having trouble with sprintf when using it with char...

CompilerGuru — Tue, 28 Oct 2008 05:09:47 GMT

Which processor, which code warrior version are you using?
The code looks fine as far as I can tell.
I saw in this forum that ColdFire is using a specially small version of printf in some case, see the thread referenced below, or search for ColdFire and printf at the bottom of this page.
Daniel

http://forums.freescale.com/freescale/board/message?board.id=CWCFCOMM&message.id=2282

BTW: For "just" converting an int to its hex representation, then probably
a dedicated function for that is much more (code and speed) effective than using printf.

Re: I am having trouble with sprintf when using it with char...

bob_s — Tue, 28 Oct 2008 19:58:04 GMT

I am running CW 8.1.1a.

I'm sure you are right. The original line of code was:
sprintf(tmpstr, "%X",(NVRAM_ADDR + (i * DATA_FLASH_SECTOR_SIZE)));
which I was using to report block data for troubleshooting flash erase and writes.

However I use sprintf to combine strings and ints into printable info for serial port echoes. I'm concerned there will be bugs in other sections of code.

Do you think I should use alternative routines for all sprintf calls?

Re: I am having trouble with sprintf when using it with char...

bob_s — Wed, 29 Oct 2008 04:22:17 GMT

For the record, by removing the sprintf lines:
sprintf(tmpstr, "%X",(NVRAM_ADDR + (i * DATA_FLASH_SECTOR_SIZE)));
sprintf(TxSplrBuf1, "%s %s\r", tmpstr, msg);

from different spots in my code and adding a routines to do the conversions, my problems went away.

I use sprintf other places in code without problems. I am running low on FLASH ROM, though I have plenty of RAM. I don't know it that is part of the problem.

Thanks for the help.

Re: I am having trouble with sprintf when using it with char...

Lundin — Wed, 29 Oct 2008 21:33:55 GMT

I don't know what is causing your problems, but I do know that sprintf() should be regarded as a hobbyist function only. There are multiple problems with that function: poor execution speed, huge nvm memory consumption, no thread safety, poor standardization of va_arg lists, and so on. As I see it, the only reason it is available is because Codewarrior want to claim ISO C compliance.

Professional embedded programmers will use their own int to string conversion routines.