topic Re: printf float format like "%3.0f" does not work in MQX Software Solutions

printf float format like "%3.0f" does not work

sandrobastos — Fri, 14 Feb 2014 11:37:32 GMT

If I use a printf/sprintf format for float like "%3.0f" it should print the float without the fractional part.

Ex.: n = 2.718 -> output should be: 2

If I use the format "%3.1f", the output should be 2.7

The problem I found in MQX 4.02 is, when I use the first example, "%3.0f", the output is 2.7, instead of 2

Exactly the same behaviour if I use "%3.1f".

It seems to me to be a bug but at "io_dopr.c" there is a code that force this situation; I commented the code (as seen below) and now it is working fine.

Could someone explain me this?

I do not like to work with a modified MQX.

Is there anyother solution for this issue?

thank you all...

case 'f':

case 'F':

if (! prec_set) {

prec = 6;

} /* Endif */

//?? /*

if (prec == 0) {

prec = 1;

}

BrunoCastelucci

rendy

karinavalencia

Re: printf float format like "%3.0f" does not work

rendy — Fri, 14 Feb 2014 12:47:11 GMT

Hi,

this is a bug. I'm creating ticket for this. Also please note, that just commenting out given lines isn't sufficient. According to GCC output for '2.718' and format "%3.0f" should be 3, not 2. This means rouding works here.

Rene

Re: printf float format like "%3.0f" does not work

sandrobastos — Fri, 14 Feb 2014 12:56:25 GMT

Hi Rene,

You are absolutely right! The number must be rounded.

Will this bug be fixed in MQX 4.1 ?

thank you - regards...

Re: printf float format like "%3.0f" does not work

sandrobastos — Fri, 14 Feb 2014 13:03:30 GMT

Dear Rene,

The rounding is already done correctly. I just checked with the 2.718 example and it works.

I had an '3' as output, i.e. it was rounded by the code.

So, just commenting that code is enough.

Thank you.

Re: printf float format like "%3.0f" does not work

rendy — Fri, 14 Feb 2014 13:07:38 GMT

Unfortunately fix of this bug cannot go to 4.1.0 because it's already in code-freeze phase. Sorry.

Re: printf float format like "%3.0f" does not work

sandrobastos — Tue, 13 May 2014 11:28:08 GMT

Hi,

I've just found another MQX double float format bug:

If the double to be printed is different from 0, it works correctly:

printf("%10.0lf\n", 1.); -----> give an "1" at stdout

If the double to be printed is 0, it adds an undesired '.':

printf("%10.0lf\n", 0.); -----> give an "0." at stdout

I'm using MQX 4.1.

Re: printf float format like "%3.0f" does not work

karina_valencia — Tue, 13 May 2014 14:24:49 GMT

Hi sandrobastos,

Please create a new discussion for your last question/issue.

Re: printf float format like "%3.0f" does not work

sandrobastos — Tue, 13 May 2014 15:47:22 GMT

Hi Karina,

This last bug is, in fact, regarding to the old one posted above - I believe that in a further version they will be fixed together.

Thank you.

Re: printf float format like "%3.0f" does not work

karina_valencia — Tue, 13 May 2014 16:09:35 GMT

rendy can you comment about previous update from Sandro please?

Re: printf float format like "%3.0f" does not work

rendy — Wed, 14 May 2014 08:14:25 GMT

Hi,

bugfix for the first will be present in MQX 4.1.1, expected release date is end of June. I confirm the second one is a bug, I've reported it but cannot confirm resolution date or version.

Re: printf float format like "%3.0f" does not work

sandrobastos — Wed, 27 Aug 2014 12:32:56 GMT

Hi Rene,

I have just updated my MQX to 4.1.1.

Unfortunately the printf with argument "%3.0f" still doesn't work. It insists in put an undesired 'dot zero' at the end of the printed number:

printf("%10.0lf\n", 3.14);

gives: '3.1' (but should be just '3')

printf("%10.1lf\n", 3.14);

gives: '3.1' (that's right)

rendy

Re: printf float format like "%3.0f" does not work

rendy — Wed, 27 Aug 2014 13:37:20 GMT

Hi, I'll check it asap.

Re: printf float format like "%3.0f" does not work

rendy — Tue, 02 Sep 2014 06:39:47 GMT

Hi, I confirm your observations. I have created a patch for this and I will send it to MQX team and push them to integrate it to the next release.

Re: printf float format like "%3.0f" does not work

sandrobastos — Tue, 02 Sep 2014 10:23:27 GMT

Hi Rene,

Yes, I did a workaround at "io_dopr.c"; there is a code that force this situation; I commented the code (as seen below) and it seems to work fine.

case 'f':

case 'F':

if (! prec_set) {

prec = 6;

} /* Endif */

//------My Workaround------------------------

//?? /*

if (prec == 0) {

prec = 1;

}

//-------------------------------------------

But a little problem still remains:

If the double to be printed is different from 0, it works correctly:

printf("%10.0lf\n", (float)1); -----> give an "1" at stdout

If the double to be printed is 0, it adds an undesired '.':

printf("%10.0lf\n", (float)0); -----> give an "0." at stdout

//-------------------------------------------

I'll try out your patch.

thank you,

regards

Re: printf float format like "%3.0f" does not work

sandrobastos — Tue, 02 Sep 2014 10:42:29 GMT

Rene,

I'm sorry but, how do I apply the '.pathc' file?

rendy

Re: Re: printf float format like "%3.0f" does not work

rendy — Tue, 02 Sep 2014 11:23:28 GMT

In Linux, you can use 'patch' utility. In Windows you can use git scm's command 'git patch'. But you don't need to use the patch if you don't want to, because the changes needed are small. First, your workaround is right but you need to add this:

In file 'io_fp.c', row 799 there is the expression:

*bp++ = '.';

You need to change it to:

if (decpt < 0)
   *bp++ = '.';

And you are done :smileycool:

Re: Re: printf float format like "%3.0f" does not work

sandrobastos — Tue, 02 Sep 2014 11:41:59 GMT

Ok, it was exactly what I did; opened the patch as a text and made manually the fixes.

It worked fine! The second fix you suggested in 'io_fp.c' solved the "0." problem.

Thank you very much Rene.

best regards,

sandro

Re: printf float format like "%3.0f" does not work

sandrobastos — Mon, 31 Aug 2015 17:30:25 GMT

Hi Rene,

18 months later this discussion, another float format problem was found.

I'm still using MQX 4.1.1, with the corrections discussed in this post.

I'm using the float format "%0.02f" to obtain outputs of type "x.yz".

If the number is, for example, 1.234, I get "1.23" ---> that's right.

But if the number is less than one, for example, 0.123, the output string is "012" (without dot) and not "0.12".

Another workaround or correction I could apply?

thank you,

sandro

rendy

karinavalencia

bfac

Re: printf float format like "%3.0f" does not work

karina_valencia — Mon, 31 Aug 2015 17:36:14 GMT

Hi Sandro,

I suggest you to create a new thread and add this link as a reference due this case was closed.