Open System Services Library Calls Reference Manual (G06.29+, H06.08+, J06.03+)

random(3) OSS Library Calls Reference Manual
NAME
random - Generates random numbers
LIBRARY
G-series native Guardian processes: $SYSTEM.SYSnn.ZSTFNSRL
G-series native OSS processes: /G/system/sysnn/zstfnsrl
H-series and J-series native Guardian processes: $SYSTEM.ZDLLnnn.ZCREDLL
32-bit H-series and J-series OSS processes: /G/system/zdllnnn/zcredll
64-bit H-series and J-series OSS processes: /G/system/zdllnnn/ycredll
SYNOPSIS
#include <stdlib.h>
long random(void);
PARAMETERS
None.
DESCRIPTION
The random( ) function generates a pseudo-random number in the range 0 (zero) to 2**31-1
using a nonlinear additive feedback random-number generator. By default, this generator uses a
state array size of 31 long integers and has an approximate period of 16*(2**31-1). If the size of
the state array is increased, the period of the random-number generator is increased. For example,
with 256 bytes of state information, the random-number generator would have a period greater
than 2**69.
If you call the random( ) function without a previous call to the initstate( ) function, it behaves
as though you had called initstate( ) with seed equal to 1 and size equal to 128.
After you have initialized a state array with the initstate( ) function, you can use the setstate( )
function to switch state arrays. Subsequent calls to the random( ) function will use the state
array pointed to by the state parameter until either initstate( ) is called or setstate( ) is called
again.
NOTES
This function can be called by native processes only.
RETURN VALUES
The random( ) function returns a pseudo-random number.
ERRORS
None. This function does not set errno.
RELATED INFORMATION
Functions: initstate(3), setstate(3), srandom(3).
STANDARDS CONFORMANCE
The random( ) function is defined in the XPG4 Version 2 specification.
5−134 Hewlett-Packard Company 527187-017