gawk: Extension Sample Time
16.7.11 Extension Time Functions
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The 'time' extension adds two functions, named 'gettimeofday()' and
'sleep()', as follows:
'@load "time"'
This is how you load the extension.
'the_time = gettimeofday()'
Return the time in seconds that has elapsed since 1970-01-01 UTC as
a floating-point value. If the time is unavailable on this
platform, return -1 and set 'ERRNO'. The returned time should have
sub-second precision, but the actual precision may vary based on
the platform. If the standard C 'gettimeofday()' system call is
available on this platform, then it simply returns the value.
Otherwise, if on MS-Windows, it tries to use
'GetSystemTimeAsFileTime()'.
'result = sleep(SECONDS)'
Attempt to sleep for SECONDS seconds. If SECONDS is negative, or
the attempt to sleep fails, return -1 and set 'ERRNO'. Otherwise,
return zero after sleeping for the indicated amount of time. Note
that SECONDS may be a floating-point (nonintegral) value.
Implementation details: depending on platform availability, this
function tries to use 'nanosleep()' or 'select()' to implement the
delay.