UNIX环境C语言编程(5)-系统数据文件

1、密码文件/etc/passwd

•#include <pwd.h>

•struct passwd *getpwuid(uid_tuid); //根据uid读取

•struct passwd *getpwnam(const char *name);//根据名称读取

•struct passwd *getpwent(void); //顺序读取

•void setpwent(void); //回绕，从头再来

•void endpwent(void); //结束

 

2、组文件/etc/group

•#include <grp.h>

•struct group *getgrgid(gid_tgid); //根据gid读取

•struct group *getgrnam(const char *name);  // 根据名称读取

•struct group *getpwent(void); //顺序读取

•void setgrent(void); //回绕，从头再来

•void endgrent(void);   //结束

 

3、其它数据文件

 

4、系统标识

•#include <sys/utsname.h>

•int uname(structutsname *name); //获取系统信息

•struct utsname

•{

•     char sysname[]; /* name of the operating system */

•     char nodename[]; /* name of this node */

•     char  release[];  /* current release of operating system */

•     char  version[];  /* current version of this release */

•     char  machine[];  /* name of hardware type */

•};

•#include <unistd.h>

•int gethostname(char *name,intnamelen); //仅获取主机名称

 

5、时间/日期函数

•#include <time.h>

•#include <sys/time.h>

•time_t time(time_t *calptr);

•int gettimeofday(structtimeval *tp, void *tzp);

•struct tm *gmtime(consttime_t *calptr);

•struct tm *localtime(consttime_t *calptr);

•time_t mktime(struct tm *tmptr);

•char *asctime(conststruct tm *tmptr);

•char *ctime(consttime_t *calptr);

•size_t strftime(char *buf,size_tmaxsize,const char *format,conststruct tm *tmptr);