forked from Telodendria/Telodendria
45 lines
1.4 KiB
Groff
45 lines
1.4 KiB
Groff
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.Dd $Mdocdate: February 16 2023 $
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.Dt RAND 3
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.Os Telodendria Project
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.Sh NAME
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.Nm Rand
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.Nd Thread-safe random numbers.
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.Sh SYNOPSIS
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.In Rand.h
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.Ft int
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.Fn RandInt "unsigned int"
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.Ft void
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.Fn RandIntN "int *" "size_t" "unsigned int"
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.Sh DESCRIPTION
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.Nm
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is used for generating random numbers in a thread-safe way. Currently,
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one seed is shared across all threads, which means only one thread can
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generate random numbers at a time. In the future, a seed pool may be
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maintained. The seed is initialized on the first call to a function
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that needs it. It is initialized with the current timestamp,
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the process ID, and the thread ID. These should be sufficiently random
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sources, so the seed should be secure enough.
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.Pp
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.Fn RandInt
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generates a single random integer between 0 and the passed value.
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.Fn RandIntN
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takes an integer pointer, a buffer size, and the maximum value a
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random number is allowed to be. It generates the number of random
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integers specified by the buffer size, and stores them at the passed
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pointer. This allows a caller to get multiple random numbers at a
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time, as each call to
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.Fn RandInt
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will have to lock and unlock a mutex, whereas
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.Fn RandIntN
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can obtain multiple random integers in a single pass.
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.Sh RETURN VALUES
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.Pp
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.Fn RandInt
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returns the value of
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.Xr rand_r 3
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with the internally-stored seed. The return value should be in the
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range of 0 to RAND_MAX.
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.Sh SEE ALSO
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.Xr Util 3 ,
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.Xr rand 3
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