The
randomid() function provides pseudo-random data stream, which is guaranteed not to generate the same number twice during a certain duration.
ctx is the context which holds internal state for the random number generator.
To initialize a context,
randomid_new is used.
bits specifies the bitwidth of the value generated by
randomid(). Currently 32, 20, and 16 are supported.
timeo specifies the reinitialization interval in seconds.
timeo has to be bigger than
RANDOMID_TIMEO_MIN.
randomid_new returns a dynamically-allocated memory region allocated by
malloc(3).
randomid_delete() will
free(3) the internal state
ctx.
The same number may appear after two reinitialization events of the internal state,
ctx. Reinitialization happens when the random number generator cycle is exhausted, or
timeo seconds have passed since the last reinitialization. For instance,
ctx configured to generate 16 bit data stream will reinitialize its internal state every 30000 calls to
randomid() (or after
timeo seconds), therefore the same data will not appear until after 30000 calls to
randomid() (or after
timeo seconds).
The internal state,
ctx, determines the data stream generated by
randomid().
ctx must be allocated per data stream (such as a specific data field). It must not be shared among multiple data streams with different usage.