sprintf formatting question

[BMillikan]

When I write a string such as the following:

sprintf(java_script,"Step: <INPUT NAME=\"angle\" TYPE=\"text\" value=\"%f\" SIZE="20">", floatVal);

It puts an "f" in the input field.

However, if I create another string and put it in that string, it will print the desired result.

For example:

char fnum[20];
sprintf(fnum,"%f",floatVal);
sprintf(java_script,"Step: <INPUT NAME=\"angle\" TYPE=\"text\" value=\"%s\" SIZE="20">", fnum);

This works.

Any ideas?

[Chris Ruff]

It's good that it works.

You have found a compiler limitation (bug?), I run into that every now and then, usually when doing something all-in-one-line.

If you have a line like:

sprintf(filbert,"%s%s%s",getfilb1(),getfilb2(),getfilb3());

there is no guarantee that the compiled code will execute getfilb1 then 2 then 3 in that order. It may execute getfilb3() first.

That one was a surprise when I wrote code that required them to be in order!

Chris

[seulater]

try using the %f with formatting. such as %4.3f i have found that not using the formatting can also cause problems at times.

[pbreed]

Are you sure its sprintf not siprintf?

siprintf does not include floating point stuff.

The normal NNDK (anything other than SBL2E and MOD5213) uses standard newlib code.
The SBL2e and MOD5213 uses a much smaller more efficent printf core written by netburner.
They should be 100% identical, but its possible we have a weird bug.

So what platform and NNDK version do you have the error on?

[tod]

re:

Any ideas?

Sure, use the C++ iostream library instead. (sorry, I have a reputation to uphold).

Also, doesn't NetBurner support the safe version snprintf? Shouldn't everyone that doesn't use the C++ iostream library being using the safe versions instead?

And maybe finally something useful: what you posted shouldn't even compile. Did you cut and paste or do it from memory? You're missing escapes on the final size = 20. When I correct those your code compiles and works for me on a MOD5272. Here's the code

Code: Select all

 const int MAX_MSG_SIZE=100;
	char msg[MAX_MSG_SIZE];
	float float_val = 45.6;
	snprintf(msg, MAX_MSG_SIZE,"Step: <INPUT NAME=\"angle\" TYPE=\"text\" value=\"%f\" SIZE=\"20\">", float_val);
	printf ("%s", msg);

Here's an image of the output: