setstate()

Updated: May 06, 2022

Reset the state of a pseudo-random number generator

Synopsis:

#include <stdlib.h>

char *setstate( const char *state );

Arguments:

state
A pointer to the state array that you want to use.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

Once the state of the pseudo-random number generator has been initialized, setstate() allows switching between state arrays. The array defined by the state argument is used for further random-number generation until initstate() is called or setstate() is called again. The setstate() function returns a pointer to the previous state array.

This function is used in conjunction with the following:

initstate()
Initialize the state of the pseudo-random number generator.
random()
Generate a pseudo-random number using a default state.
srandom()
Set the seed used by the pseudo-random number generator.

After initialization, you can restart a state array at a different point in one of two ways:

Returns:

A pointer to the previous state array, or NULL if an error occurred.

Examples:

See initstate().

Classification:

POSIX 1003.1

Safety:  
Cancellation point No
Interrupt handler No
Signal handler No
Thread No