esp_timer_get_time returning uint64_t but function declares itself as int64_t (IDFGH-15193)

[NigelGuyLeeming]

Answers checklist.

• I have read the documentation ESP-IDF Programming Guide and the issue is not addressed there.
• I have updated my IDF branch (master or release) to the latest version and checked that the issue is present there.
• I have searched the issue tracker for a similar issue and not found a similar issue.

General issue report

esp_timer_get_time is declared
int64_t esp_timer_get_time(void) attribute((alias("esp_timer_impl_get_time")));
which in turn is declared
int64_t ESP_TIMER_IRAM_ATTR esp_timer_impl_get_time(void)
{
return esp_timer_impl_get_counter_reg() / TICKS_PER_US;
}
and calls
uint64_t ESP_TIMER_IRAM_ATTR esp_timer_impl_get_counter_reg(void)

this [return esp_timer_impl_get_counter_reg() / TICKS_PER_US;] will return a uint64_t.

Steps to reproduce in arduino ide

1. Paste the following code
   int64_t times[15];
   uint64_t timesu[15];
   int count=0;

void setup() {
Serial.begin(115200);
}
void loop() {
times[0]=esp_timer_get_time();
timesu[0]=esp_timer_get_time();
delayMicroseconds(200);
times[1]=esp_timer_get_time();
timesu[1]=esp_timer_get_time();
times[2]=esp_timer_get_time();
timesu[2]=esp_timer_get_time();
Serial.println("int64_t");
Serial.printf("Raw times: %lld %lld %lld\n", times[0], times[1], times[2]);
Serial.printf("Raw timesu: %llu %llu %llu\n", timesu[0], timesu[1], timesu[2]);
Serial.println("uint64_t");
Serial.printf("Diff times: %lld %lld\n", times[1]-times[0], times[2]-times[0]);
Serial.printf("Diff timesu: %llu %llu\n", timesu[1]-timesu[0], timesu[2]-timesu[0]);

delay(2000);

}

2. Run and observe serial output
   12:58:30.371 -> int64_t
   12:58:30.371 -> Raw times: -5611473693289987786 2098724293209941280 -1945483338840014608
   12:58:30.371 -> Raw timesu: 1226138255 1226138456 1226138457
   12:58:30.371 -> uint64_t
   12:58:30.371 -> Diff times: 7710197986499929066 3665990354449973178
   12:58:30.371 -> Diff timesu: 201 202

The raw and diff times stored as int64_t are meaningless. raw and diff for uint64_t are correct.

[me-no-dev]

@Alvin1Zhang this is not an Arduino issue. esp_timer_get_time() is part of ESP-IDF