#define _TIMESPEC_DEFINED struct timespec { time_t tv_sec; long tv_nsec; };
The given code snippet defines a structure in the C programming language called "timespec" using the preprocessor directive #define
.
Step 1: Preprocessor Directive
The preprocessor directive #define
is used to define a macro in C. In this case, the macro being defined is _TIMESPEC_DEFINED
. The macro is a symbolic name that can be used to represent a value or a block of code. It is used to ensure that the structure definition is not repeated if the code is included multiple times.
Step 2: Structure Definition
The structure definition begins with the keyword struct
followed by the name of the structure, which is timespec
. The structure contains two members: tv_sec
of type time_t
and tv_nsec
of type long
.
Step 3: Member Variables
The member variables tv_sec
and tv_nsec
represent the seconds and nanoseconds of a time value, respectively. The time_t
type is used to represent time in seconds, while long
is a data type that can hold a larger range of integer values.
By defining this structure, the code provides a way to store and manipulate time values with precision up to nanoseconds.