man3/drand48_r.3

   1 .\" Copyright 2003 Walter Harms, 2004 Andries Brouwer <aeb@cwi.nl>.
   2 .\"
   3 .\" SPDX-License-Identifier: Linux-man-pages-copyleft
   4 .\"
   5 .\" Created 2004-10-31. Text taken from a page by Walter Harms, 2003-09-08
   6 .\"
   7 .TH DRAND48_R 3 2021-03-22 "Linux man-pages (unreleased)" "Linux Programmer's Manual"
   8 .SH NAME
   9 drand48_r, erand48_r, lrand48_r, nrand48_r, mrand48_r, jrand48_r,
  10 srand48_r, seed48_r, lcong48_r
  11 \- generate uniformly distributed pseudo-random numbers reentrantly
  12 .SH LIBRARY
  13 Standard C library
  14 .RI ( libc ", " \-lc )
  15 .SH SYNOPSIS
  16 .nf
  17 .B #include <stdlib.h>
  18 .PP
  19 .BI "int drand48_r(struct drand48_data *restrict " buffer ,
  20 .BI "              double *restrict " result );
  21 .BI "int erand48_r(unsigned short " xsubi [3] ","
  22 .BI "              struct drand48_data *restrict "buffer ,
  23 .BI "              double *restrict " result ");"
  24 .PP
  25 .BI "int lrand48_r(struct drand48_data *restrict " buffer ,
  26 .BI "              long *restrict " result );
  27 .BI "int nrand48_r(unsigned short " xsubi[3] ","
  28 .BI "              struct drand48_data *restrict "buffer ,
  29 .BI "              long *restrict " result ");"
  30 .PP
  31 .BI "int mrand48_r(struct drand48_data *restrict " buffer ,
  32 .BI "              long *restrict " result ");"
  33 .BI "int jrand48_r(unsigned short " xsubi[3] ","
  34 .BI "              struct drand48_data *restrict " buffer ,
  35 .BI "              long *restrict " result ");"
  36 .PP
  37 .BI "int srand48_r(long int " seedval ", struct drand48_data *" buffer ");"
  38 .BI "int seed48_r(unsigned short " seed16v[3] ", struct drand48_data *" buffer );
  39 .BI "int lcong48_r(unsigned short " param[7] ", struct drand48_data *" buffer );
  40 .fi
  41 .PP
  42 .RS -4
  43 Feature Test Macro Requirements for glibc (see
  44 .BR feature_test_macros (7)):
  45 .RE
  46 .PP
  47 All functions shown above:
  48 .\" .BR drand48_r (),
  49 .\" .BR erand48_r (),
  50 .\" .BR lrand48_r (),
  51 .\" .BR nrand48_r (),
  52 .\" .BR mrand48_r (),
  53 .\" .BR jrand48_r (),
  54 .\" .BR srand48_r (),
  55 .\" .BR seed48_r (),
  56 .\" .BR lcong48_r ():
  57 .nf
  58     /* Glibc since 2.19: */ _DEFAULT_SOURCE
  59         || /* Glibc <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
  60 .fi
  61 .SH DESCRIPTION
  62 These functions are the reentrant analogs of the functions described in
  63 .BR drand48 (3).
  64 Instead of modifying the global random generator state, they use
  65 the supplied data
  66 .IR buffer .
  67 .PP
  68 Before the first use, this struct must be initialized, for example,
  69 by filling it with zeros, or by calling one of the functions
  70 .BR srand48_r (),
  71 .BR seed48_r (),
  72 or
  73 .BR lcong48_r ().
  74 .SH RETURN VALUE
  75 The return value is 0.
  76 .SH ATTRIBUTES
  77 For an explanation of the terms used in this section, see
  78 .BR attributes (7).
  79 .ad l
  80 .nh
  81 .TS
  82 allbox;
  83 lbx lb lb
  84 l l l.
  85 Interface       Attribute       Value
  86 T{
  87 .BR drand48_r (),
  88 .BR erand48_r (),
  89 .BR lrand48_r (),
  90 .BR nrand48_r (),
  91 .BR mrand48_r (),
  92 .BR jrand48_r (),
  93 .BR srand48_r (),
  94 .BR seed48_r (),
  95 .BR lcong48_r ()
  96 T}      Thread safety   MT-Safe race:buffer
  97 .TE
  98 .hy
  99 .ad
 100 .sp 1
 101 .SH STANDARDS
 102 These functions are GNU extensions and are not portable.
 103 .SH SEE ALSO
 104 .BR drand48 (3),
 105 .BR rand (3),
 106 .BR random (3)