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| author | Alejandro Colomar <alx@kernel.org> | 2022-12-29 18:13:23 +0100 |
|---|---|---|
| committer | Alejandro Colomar <alx@kernel.org> | 2022-12-29 18:13:54 +0100 |
| commit | 8341e8b683f1e9582956a8a98065865a96b0798f (patch) | |
| tree | 83e9770059623bf56d0ef2d1ccf011de08c418d0 | |
| parent | 72b349dd8c209d7375d4d4f76e2315943d654ee9 (diff) | |
| download | man-pages-8341e8b683f1e9582956a8a98065865a96b0798f.tar.gz | |
rand.3: EXAMPLES: Show how to get a random seed
This is useful when testing many different cases, but repeatability is
more important than quality of the random numbers.
Cc: Jonny Grant <jg@jguk.org>
Cc: Cristian RodrÃguez <crrodriguez@opensuse.org>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
| -rw-r--r-- | man3/rand.3 | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/man3/rand.3 b/man3/rand.3 index 5b9e21abea..e7778655e5 100644 --- a/man3/rand.3 +++ b/man3/rand.3 @@ -190,6 +190,9 @@ The following program can be used to display the pseudo-random sequence produced by .BR rand () when given a particular seed. +When the seed is +.IR \-1 , +the program uses a random seed. .PP .in +4n .\" SRC BEGIN (rand.c) @@ -211,6 +214,11 @@ main(int argc, char *argv[]) seed = atoi(argv[1]); nloops = atoi(argv[2]); + if (seed == \-1) { + seed = arc4random(); + printf("seed: %u\en", seed); + } + srand(seed); for (unsigned int j = 0; j < nloops; j++) { r = rand(); |