How Can I Measure Time in Nanoseconds Using C ?

Measuring Time in Nanoseconds with C

Problem:

When using C functions, it's common to measure the time it takes for an API to return a value. However, the standard clock() function often measures time in seconds, which is insufficient for nanosecond-level precision.

Solution:

To achieve higher precision in time measurement, you can utilize alternative functions and operating system-specific methods.

Linux/BSD:

For Linux and BSD systems, the clock_gettime() function can be used:

#include <sys/time.h>

int main() {
    timespec ts;
    clock_gettime(CLOCK_MONOTONIC, &ts);
}

Windows:

In Windows, the QueryPerformanceCounter function can be used:

#include <Windows.h>

int main() {
    LARGE_INTEGER ts;
    QueryPerformanceCounter(&ts);
}

Notes:

• Be aware of potential issues with QueryPerformanceCounter on certain chipsets, such as AMD dual core CPUs.
• Consider using the clock_gettime() function for Windows XP Service Pack 2 or later for improved accuracy.
• Reference the resources provided in the answer for further details on timer functionality and potential pitfalls.

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