drand48_r

DRAND48_R(3)               Linux Programmer's Manual              DRAND48_R(3)

NAME
       drand48_r,   erand48_r,  lrand48_r,  nrand48_r,  mrand48_r,  jrand48_r,
       srand48_r, seed48_r, lcong48_r - generate uniformly distributed pseudo-
       random numbers reentrantly

SYNOPSIS
       #include <stdlib.h>

       int drand48_r(struct drand48_data *buffer, double *result);

       int erand48_r(unsigned short xsubi[3],
                     struct drand48_data *buffer, double *result);

       int lrand48_r(struct drand48_data *buffer, long int *result);

       int nrand48_r(unsigned short int xsubi[3],
                     struct drand48_data *buffer, long int *result);

       int mrand48_r(struct drand48_data *buffer,long int *result);

       int jrand48_r(unsigned short int xsubi[3],
                     struct drand48_data *buffer, long int *result);

       int srand48_r(long int seedval, struct drand48_data *buffer);

       int seed48_r(unsigned short int seed16v[3],
                    struct drand48_data *buffer);

       int lcong48_r(unsigned short int param[7],
                     struct drand48_data *buffer);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       All functions shown above:
           /* Glibc since 2.19: */ _DEFAULT_SOURCE
               || /* Glibc versions <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE

DESCRIPTION
       These functions are the reentrant analogs of the functions described in
       drand48(3).  Instead of modifying the global  random  generator  state,
       they use the supplied data buffer.

       Before  the first use, this struct must be initialized, for example, by
       filling it with zeros, or by calling one of the functions  srand48_r(),
       seed48_r(), or lcong48_r().

RETURN VALUE
       The return value is 0.

ATTRIBUTES
       For  an  explanation  of  the  terms  used  in  this  section,  see at-
       tributes(7).

       +--------------------------+---------------+---------------------+
       |Interface                 | Attribute     | Value               |
       +--------------------------+---------------+---------------------+
       |drand48_r(), erand48_r(), | Thread safety | MT-Safe race:buffer |
       |lrand48_r(), nrand48_r(), |               |                     |
       |mrand48_r(), jrand48_r(), |               |                     |
       |srand48_r(), seed48_r(),  |               |                     |
       |lcong48_r()               |               |                     |
       +--------------------------+---------------+---------------------+
CONFORMING TO
       These functions are GNU extensions and are not portable.

SEE ALSO
       drand48(3), rand(3), random(3)

COLOPHON
       This page is part of release 5.05 of the Linux  man-pages  project.   A
       description  of  the project, information about reporting bugs, and the
       latest    version    of    this    page,    can     be     found     at
       https://www.kernel.org/doc/man-pages/.

GNU                               2017-09-15                      DRAND48_R(3)