drand48_r函数用法详解

drand48_r函数简介

• 头文件包含

#include <stdlib.h>

• 函数定义

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 );

drand48_r函数常见使用错误

• 编译错误
  warning: implicit declaration of function ‘drand48_r’ [-Wimplicit-function-declaration]
  解决办法：包含头文件

#include <stdlib.h>

drand48_r函数详细描述

这些函数是drand48 (3)中描述的函数的可重入类似物，它们使用提供的数据buffer 而不是修改全局随机生成器状态
在第一次使用之前，必须初始化这个结构，例如，用零填充它，或者调用函数srand48_r ()、seed48_r ()或lcong48_r ()之一

drand48_r函数返回值

返回值为0。