This is the mail archive of the ecos-discuss@sourceware.org mailing list for the eCos project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: diag_printf and float problem


Tomasz Kutyla wrote:


It seems to be some tiny problem but it happens;)


My code looks like below:

float f  = 10.5;
diag_printf("Test F = %f", f);

and on the terminal I've got:
Test F = %f

Why is that??

diag_printf() doesn't support floating point. If you need to print floating point values, you'll need to use the stdio printf() function.
Thanks Gary, now it works;) Funny thing occurs: when I use printf like this:

diag_printf("test diag\n");
printf("##Test F = %.1f", f);

system waits for some printf functions to put the stream to the terminal. So I got:

test diag
test diag
test diag
test diag
##Test F = 10.5##Test F = 10.5##Test F = 10.5##Test F = 10.5##Test F = 10.5##Test F = 10.5##Test F = 10.5
test diag
test diag
test diag
test diag
test diag
##Test F = 10.5##Test F = 10.5##Test F = 10.5##Test F = 10.5##Test F = 10.5##Test F = 10.5##Test F = 10.5


But when I use printf like this:

diag_printf("test diag\n");
printf("##Test F = %.1f\n", f);

I got on the terminal:

test diag
##Test F = 10.5
test diag
##Test F = 10.5
test diag
##Test F = 10.5
test diag
##Test F = 10.5

I'm writing it because maybe it will help somebody in the future with the situation like mine;)

This is totally expected behaviour. diag_printf() is not buffered, so whatever you print comes out immediately. printf() is buffered - nothing is actually printed until the buffer gets full or you print a newline (\n).

Try running the same code on Linux - use fprintf(stderr, ...) where you have
diag_printf() and you'll see more or less the same behaviour.



--
------------------------------------------------------------
Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
------------------------------------------------------------

--
Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]