drand48_r (3) - Linux Manuals

drand48_r: generate uniformly distributed pseudo-random numbers reentrantly

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 *result);

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

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

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

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

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

int lcong48_r(unsigned short 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 attributes(7).

Interface	Attribute	Value
drand48_r(), erand48_r(), lrand48_r(), nrand48_r(), mrand48_r(), jrand48_r(), srand48_r(), seed48_r(), lcong48_r()	Thread safety	MT-Safe race:buffer

CONFORMING TO

These functions are GNU extensions and are not portable.

COLOPHON

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