Unable to convert number to uint8_t using sscanf

[rgujju]

Hi,

I am trying to convert the string from ctime to a struct but i always get garbage values if i use "uint8_t". But i can get correct values if i use "int" datatype. I want to do it using uint8_t as it will save some space, as the numbers wont be above 255 anyway. Do i need unable some flags in the gcc Makefile?

UINT8_T:

struct time_struct {
char wday[4];
char month[4];
uint8_t month_num;
uint8_t mday;
uint8_t mil_hour;
uint8_t hour;
uint8_t min;
uint8_t sec;
int year;
};

struct time_struct now;

time_t epoch = 1548617880;
sscanf(ctime(&epoch),"%s %s %d %d:%d:%d %d",now->wday, now->month, &now->mday, &now->mil_hour, &now->min, &now->sec, &now->year);
NRF_LOG_INFO("%s %s %hhd",now->wday, now->month, now->mday);
NRF_LOG_INFO("%d:%d:%d %d", now->mil_hour, now->min, now->sec, now->year);
NRF_LOG_FLUSH();

//Output:
/*
<info> app: Sun Jan 27
<info> app: 19:38:6 2019
*/

INT:
struct time_struct {
char wday[4];
char month[4];
uint8_t month_num;
int mday;
int mil_hour;
uint8_t hour;
int min;
int sec;
int year;
};

struct time_struct now;

sscanf(ctime(&epoch),"%s %s %hhd %hhd:%hhd:%hhd %d",now->wday, now->month, &now->mday, &now->mil_hour, &now->min, &now->sec, &now->year);
NRF_LOG_INFO("%s %s %hhd",now->wday, now->month, now->mday);
NRF_LOG_INFO("%hhd:%hhd:%hhd %d", now->mil_hour, now->min, now->sec, now->year);
NRF_LOG_FLUSH();

// Output:
/*
<info> app: Sun Jan 27
<info> app: 0:65:34 19059
* /

thanks.

[Turbo J]

The sscanf() function requires that the destination for the "%d" conversion is 4 bytes - sizeof(int) wide. This will overwrite adjacent fields in your struct of uint8_t values.

Workaround: Use temporary int variables on the stack.

[rgujju]

then what format specifier should i use to convert to 1 byte? I have tried with %c as well, and it doesnt seem to work.