sscanf compilation error

[nicjohnston]

I recently tried to use sscanf, however the compiler threw an undefined reference error.
Replacing sscanf with os_sprintf as recommended in issue #404 did not solve it, instead it created a watchdog timer reboot.
Here is the code I was using:

void setup() {
  Serial.begin(115200);
  Serial.println("starting");
  char *data = "1234";
  int i = 0;
  sscanf(data,"%d", &i);
  Serial.println(i);
}
void loop() { }

Any suggestions would be appreciated.

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[chadouming]

You need os_scanf and not os_sprintf

On Mon, Jun 29, 2015, 7:04 PM nicjohnston notifications@github.com wrote:

I recently tried to use sscanf, however the compiler threw an undefined
reference error.
Replacing sscanf with os_sprintf as recommended in issue #404
#404 did not solve it, instead
it created a watchdog timer reboot.
Here is the code I was using:

void setup() {
Serial.begin(115200);
Serial.println("starting");
char *data = "1234";
int i = 0;
sscanf(data,"%d", &i);
Serial.println(i);
}void loop() { }

Any suggestions would be appreciated.

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#488.

[nicjohnston]

Thanks for the reply, however I just tried os_scanf, and it threw the following error

error: 'os_scanf' was not declared in this scope

[chadouming]

what are you trying to do ?
scanf is intended to read an input from the user. If you want to take the content of "i" and put it in the char buffer "data", then you would do :

void setup() {
Serial.begin(115200);
Serial.println("starting");
char *data = "";
int i = 0;
sprintf(data,"%d", i);
Serial.println(i);
}

Serial output should be :

Starting
0

Also, don't forget that sprintf on arduino doesnt support float or double. Just in case you wanted to use these types.

[nicjohnston]

I am attempting to extract an integer value from a char buffer into a variable; I probably should have specified this sooner.
This issue surfaced while attempting to compile the ArduinoIMU example sketch from this library.
Does this esp8266 library have support for sscanf? If not, could you point me in the right direction to add it myself?
Thanks.

[chadouming]

Ok, so this might be a dirty hack, but can you try :

char *buff2 = "24";
int i = ((String)(buff2)).toInt();

Worked fine for me even tho it made a warning.

[Links2004]

String is a class not a type.
warning free:

char buff2[] = "24";
int i = String(buff2).toInt();
Serial.println(i);

[nicjohnston]

Thanks for reminding me about toInt, however the toInt function doesn't support parsing multiple variables from a char array.
This should have been in my previous post, but a more representative string is "1500,2100,1200,0". The example code used a single variable string to make debugging easier.
I could loop through the array and find every delimiting character in order to split it up into separate arrays and then convert those to integers using the toInt function, however I use sscanf to parse data in many of the sketches I would like to port to the ESP8266. Because of this, either a drop in replacement for sscanf or a patch for sscanf would be preferable.

[a-andreyev]

completely agree with @nicjohnston, we should implement siscanf(...)

[Toshik]

Any news about sscanf?

[torntrousers]

I'm looking to parse an HTTP Date header - "Thu, 15 Oct 2015 08:57:03 GMT" - into day, hours, minutes etc - I'd like sscanf too.

[lighthousebulb]

any ideas for a workaround yet?

[a-andreyev]

@lighthousebulb, I guess current ugly workaround is to use Arduino String.

[Toshik]

@a-andreyev How do you suppose to use String instead of sscanf?

[andig]

+1 for sscanf as its available on "standard" Arduino.