I'm using the following routine to print the current time on the com port. I would like to capture this as a string so I can display it using ePaper.
void printLocalTime()
{
time_t rawtime;
struct tm timeinfo;
if(!getLocalTime(&timeinfo))
{
Serial.println("Failed to obtain time");
return;
}
Serial.println(&timeinfo, "%A, %B %d %Y %H:%M:%S");
}
produces -
Saturday, May 12 2018 12:18:27
To achieve what you want you probably want to use the "string format time" function strftime (docs). You would write the result in a character buffer, which you can also print directly without having to convert it to String object.
So, the following code should work:
void printLocalTime()
{
time_t rawtime;
struct tm timeinfo;
if(!getLocalTime(&timeinfo))
{
Serial.println("Failed to obtain time");
return;
}
char timeStringBuff[50]; //50 chars should be enough
strftime(timeStringBuff, sizeof(timeStringBuff), "%A, %B %d %Y %H:%M:%S", &timeinfo);
//print like "const char*"
Serial.println(timeStringBuff);
//Optional: Construct String object
String asString(timeStringBuff);
}
The overload for Serial.print also does this exact same thing:
size_t Print::print(struct tm * timeinfo, const char * format)
{
const char * f = format;
if(!f){
f = "%c";
}
char buf[64];
size_t written = strftime(buf, 64, f, timeinfo);
print(buf);
return written;
}
