diff options
Diffstat (limited to 'man3/drand48.3')
| -rw-r--r-- | man3/drand48.3 | 43 |
1 files changed, 21 insertions, 22 deletions
diff --git a/man3/drand48.3 b/man3/drand48.3 index b768d0d..18123b0 100644 --- a/man3/drand48.3 +++ b/man3/drand48.3 @@ -8,7 +8,7 @@ .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) .\" 386BSD man pages .\" Modified Sat Jul 24 19:46:03 1993 by Rik Faith (faith@cs.unc.edu) -.TH drand48 3 2023-07-20 "Linux man-pages 6.05.01" +.TH drand48 3 2023-10-31 "Linux man-pages 6.7" .SH NAME drand48, erand48, lrand48, nrand48, mrand48, jrand48, srand48, seed48, lcong48 \- generate uniformly distributed pseudo-random numbers @@ -18,26 +18,26 @@ Standard C library .SH SYNOPSIS .nf .B #include <stdlib.h> -.PP +.P .B double drand48(void); .BI "double erand48(unsigned short " xsubi [3]); -.PP +.P .B long lrand48(void); .BI "long nrand48(unsigned short " xsubi [3]); -.PP +.P .B long mrand48(void); .BI "long jrand48(unsigned short " xsubi [3]); -.PP +.P .BI "void srand48(long " seedval ); .BI "unsigned short *seed48(unsigned short " seed16v [3]); .BI "void lcong48(unsigned short " param [7]); .fi -.PP +.P .RS -4 Feature Test Macro Requirements for glibc (see .BR feature_test_macros (7)): .RE -.PP +.P All functions shown above: .\" .BR drand48 (), .\" .BR erand48 (), @@ -56,7 +56,7 @@ All functions shown above: .SH DESCRIPTION These functions generate pseudo-random numbers using the linear congruential algorithm and 48-bit integer arithmetic. -.PP +.P The .BR drand48 () and @@ -64,21 +64,21 @@ and functions return nonnegative double-precision floating-point values uniformly distributed over the interval [0.0,\ 1.0). -.PP +.P The .BR lrand48 () and .BR nrand48 () functions return nonnegative long integers uniformly distributed over the interval [0,\ 2\[ha]31). -.PP +.P The .BR mrand48 () and .BR jrand48 () functions return signed long integers uniformly distributed over the interval [\-2\[ha]31,\ 2\[ha]31). -.PP +.P The .BR srand48 (), .BR seed48 (), @@ -97,17 +97,17 @@ and .BR jrand48 () do not require an initialization function to be called first. -.PP +.P All the functions work by generating a sequence of 48-bit integers, .IR Xi , according to the linear congruential formula: -.PP +.P .in +4n .EX .B Xn+1 = (aXn + c) mod m, where n >= 0 .EE .in -.PP +.P The parameter .I m = 2\[ha]48, hence 48-bit integer arithmetic is performed. @@ -118,14 +118,14 @@ is called, and .I c are given by: -.PP +.P .in +4n .EX .B a = 0x5DEECE66D .B c = 0xB .EE .in -.PP +.P The value returned by any of the functions .BR drand48 (), .BR erand48 (), @@ -143,7 +143,7 @@ be returned, is copied from the high-order bits of .I Xi and transformed into the returned value. -.PP +.P The functions .BR drand48 (), .BR lrand48 (), @@ -169,7 +169,7 @@ value of .I Xi into the array before calling the function for the first time. -.PP +.P The initializer function .BR srand48 () sets the high order 32-bits of @@ -178,7 +178,7 @@ to the argument .IR seedval . The low order 16-bits are set to the arbitrary value 0x330E. -.PP +.P The initializer function .BR seed48 () sets the value of @@ -192,7 +192,7 @@ previous value of is copied into an internal buffer and a pointer to this buffer is returned by .BR seed48 (). -.PP +.P The initialization function .BR lcong48 () allows the user to specify @@ -249,8 +249,7 @@ T} Thread safety T{ MT-Unsafe race:drand48 T} .TE -.sp 1 -.PP +.P The above functions record global state information for the random number generator, so they are not thread-safe. |