VS Code demote CLOCK_MONOTONIC as undefined

Question

VS Code (v1.63.2), running on Linux Ubuntu 18.04, in the default setup denotes the CLOCK_MONOTONIC as undefined.

#include <time.h>
...
struct timespec start_time;
(void) clock_gettime(CLOCK_MONOTONIC, &start_time);

How should I configure VS code to have CLOCK_MONOTONIC defined?

Answer 1

The fix is to edit the c_cpp_properties.json to use gcc and define _POSIX_C_SOURCE=199309L. For example:

{
    "configurations": [
        {
            "name": "Linux",
            "includePath": [
                "${workspaceFolder}/**"
            ],
            "defines": [
                "_POSIX_C_SOURCE=199309L"
            ],
            "compilerPath": "/usr/bin/gcc",
            "cStandard": "c17",
            "cppStandard": "c++14",
            "intelliSenseMode": "linux-gcc-x64"
        }
    ],
    "version": 4
}