`timespec_get`, `_timespec32_get`, `_timespec64_get`

2025-10-25

Sets the interval pointed to by the first argument to the current calendar time, based on the specified time base.

Syntax

int timespec_get( // See note in remarks section about linkage
    struct timespec* const time_spec,
    int const base
);
int _timespec32_get(
    struct _timespec32* const time_spec,
    int const base
);
int _timespec64_get(
    struct _timespec64* const time_spec,
    int const base
);

Parameters

time_spec
Pointer to a struct that is set to the time in seconds and nanoseconds since the start of the epoch.

base
A non-zero implementation-specific value that specifies the time base.

Return value

The value of base if successful, otherwise it returns zero.

Remarks

The timespec_get functions set the current time in the struct pointed to by the time_spec argument. All versions of this struct have two members, tv_sec and tv_nsec. The tv_sec value is set to the whole number of seconds and tv_nsec to the integral number of nanoseconds, rounded to the resolution of the system clock, since the start of the epoch specified by base.

Microsoft Specific

These functions support only TIME_UTC as the base value. TIME_UTC sets the time_spec value to the number of seconds and nanoseconds since the epoch start, Midnight, January 1, 1970, Coordinated Universal Time (UTC). In a _timespec32, tv_sec is a __time32_t value. In a _timespec64, tv_sec is a __time64_t value. In a timespec, tv_sec is a time_t type, which is 32 bits or 64 bits in length depending on whether the preprocessor macro _USE_32BIT_TIME_T is defined. The timespec_get function is an inline function that calls _timespec32_get if _USE_32BIT_TIME_T is defined; otherwise it calls _timespec64_get.

End Microsoft Specific

By default, this function's global state is scoped to the application. To change this behavior, see Global state in the CRT.

Note

When you use Windows SDK version 10.0.26100.6901 and Visual Studio 2026 or later together, timespec_get is no longer static inline (internal linkage). Instead, it's inline (external linkage).
To return to the previous behavior, #define _STATIC_INLINE_UCRT_FUNCTIONS=1 before including any CRT headers. By default, _STATIC_INLINE_UCRT_FUNCTIONS is set to 0.
This change increases UCRT conformance with the C++ standard and improves compatibility with C++ modules.

Requirements

Routine	Required header
`timespec_get`, `_timespec32_get`, `_timespec64_get`	C: <time.h>, C++: <ctime> or <time.h>

For more compatibility information, see Compatibility.

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timespec_get, _timespec32_get, _timespec64_get