Hi.
I'm using sscanf trying to parse the response of an AT command sent to a GSM module. It's something very similar to the minimal working example that follows:
#include <stdint.h>
#include <stdio.h>
#include <asf.h>
int main (void)
{
char response[] = "+CGREG: 0,1";
uint8_t n, stat;
system_init();
sscanf(response, "+CGREG: %hhu,%hhu", &n, &stat);
return 0;
}The problem is that sscanf never returns back. When I paused the debugger, this was the call stack:
> sscanfTest.elf! Dummy_Handler Line: 284 sscanfTest.elf! <signal handler called> Line: 284 sscanfTest.elf! _scanf_i Line: 284 sscanfTest.elf! __ssvfscanf_r Line: 284 sscanfTest.elf! sscanf Line: 284 sscanfTest.elf! main Line: 12
I think there's an exception going on, and that would be handled by this Dummy_Handler, which is just a while (1) { }. Initially I thought it could a missing part of the C library, so I tried adding libc in the linker. I also tried to uncheck the nano.specs option, thinking that maybe sscanf required the full C library to work. Unfortunatelly, none of these work. I know there are some libraries needed when one intends to work with floating point numbers, which is not the case.
I'm programming a SAMD21 microcontroller using Atmel Studio 7.0 and ASF. Interestingly, ssprintf works just fine.
So, if anybody has an idea about what can be the causing this problem, I appreciate. Thanks!