Hi! ESP32 project on the Arduino framework: I'm trying to parse a time string "8:00AM" like this:
strptime(timestr, "%I:%M%p", &tmobject);
...it works, but it does not parse the AM/PM correctly: it is always PM in the resulting tm struct.
I have read that %p depends on the locale, which may not have am/pm values set, so I tried looking into how to set that and came up empty. I tried all of these:
setlocale(LC_TIME, "en_US")
setlocale(LC_TIME, "en_US.utf8")
setlocale(LC_ALL, "en_US")
setlocale(LC_ALL, "en_US.utf8")
...but those calls all return NULL, which indicates that they did not work.
I can parse the AM/PM myself manually, but I'd love to just have strptime do it. Is there a secret to making this work? Is there documentation anywhere about how locales are handled in this context? I didn't google anything up.
Here's a full demo program. This prints "hour is 20" on the ESP32. The analgous program on my desktop prints "hour is 8" as expected.
#include <Arduino.h>
#include <stdio.h>
#include <stdlib.h>
#include <locale.h>
#include <time.h>
void setup()
{
Serial.begin(115200);
while (!Serial) delay(10);
char timestr[7] = "8:00AM";
static struct tm temptm;
static time_t temptime;
temptime = time(NULL);
temptm = *localtime(&temptime);
strptime(timestr, "%I:%M%p", &temptm);
Serial.printf("hour is %d\n", temptm.tm_hour);
}
void loop()
{
delay(100);
}
