Linux程序设计入门 系统进程的详细介绍

#include ＜unistd＞ 
pid_t getpid(void); 
            pid_t getppid(void);

#include ＜unistd＞ 
#include ＜sys/types.h＞ 
uid_t getuid(void); 
uid_t geteuid(void); 
gid_t getgid(void); 
            git_t getegid(void);

struct passwd { 
char *pw_name; /* 登录名称 */ 
char *pw_passwd; /* 登录口令 */ 
uid_t pw_uid; /* 用户ID */ 
gid_t pw_gid; /* 用户组ID */ 
char *pw_gecos; /* 用户的真名 */ 
char *pw_dir; /* 用户的目录 */ 
char *pw_shell; /* 用户的SHELL */ 
}; 
#include ＜pwd.h＞ 
#include ＜sys/types.h＞ 
            struct passwd *getpwuid(uid_t uid);

#include ＜unistd.h＞ 
#include ＜pwd.h＞ 
#include ＜sys/types.h＞ 
#include ＜stdio.h＞ 
int main(int argc,char **argv) 
{ 
pid_t my_pid,parent_pid; 
uid_t my_uid,my_euid; 
gid_t my_gid,my_egid; 
struct passwd *my_info; 
my_pid=getpid(); 
parent_pid=getppid(); 
my_uid=getuid(); 
my_euid=geteuid(); 
my_gid=getgid(); 
my_egid=getegid(); 
my_info=getpwuid(my_uid); 
printf("Process ID:%ld ",my_pid); 
printf("Parent ID:%ld ",parent_pid); 
printf("User ID:%ld ",my_uid); 
printf("Effective User ID:%ld ",my_euid); 
printf("Group ID:%ld ",my_gid); 
printf("Effective Group ID:%ld ",my_egid): 
if(my_info) 
{ 
printf("My Login Name:%s " ,my_info-＞pw_name); 
printf("My Password :%s " ,my_info-＞pw_passwd); 
printf("My User ID :%ld ",my_info-＞pw_uid); 
printf("My Group ID :%ld ",my_info-＞pw_gid); 
printf("My Real Name:%s " ,my_info-＞pw_gecos); 
printf("My Home Dir :%s ", my_info-＞pw_dir); 
printf("My Work Shell:%s ", my_info-＞pw_shell); 
} 
            }

#include ＜unistd.h＞ 
            pid_t fork();

#include ＜sys/types.h＞ 
#include ＜sys/wait.h＞ 
pid_t wait(int *stat_loc); 
            pid_t waitpid(pid_t pid,int *stat_loc,int options);