=over =item srand EXPR X X X =item srand Sets the random number seed for the C operator. The point of the function is to "seed" the C function so that C can produce a different sequence each time you run your program. If srand() is not called explicitly, it is called implicitly at the first use of the C operator. However, this was not true of versions of Perl before 5.004, so if your script will run under older Perl versions, it should call C. Most programs won't even call srand() at all, except those that need a cryptographically-strong starting point rather than the generally acceptable default, which is based on time of day, process ID, and memory allocation, or the F device if available. You can call srand($seed) with the same $seed to reproduce the I sequence from rand(), but this is usually reserved for generating predictable results for testing or debugging. Otherwise, don't call srand() more than once in your program. Do B call srand() (i.e., without an argument) more than once in a script. The internal state of the random number generator should contain more entropy than can be provided by any seed, so calling srand() again actually I randomness. Most implementations of C take an integer and will silently truncate decimal numbers. This means C will usually produce the same results as C. To be safe, always pass C an integer. In versions of Perl prior to 5.004 the default seed was just the current C