struct sigevent
The
struct sigevent {
int sigev_notify; //Notification type.
int sigev_signo; //Signal number.
union sigval sigev_value; //Signal value.
void (*sigev_notify_function)(union sigval); //Notification function.
pthread_attr_t *sigev_notify_attributes; //Notification attributes.
};
sigev_notify
sigev_notify 的取值范围如下,只有3种情况（对应的宏在
1.SIGEV_NONE
事件发生时,什么也不做.
2.SIGEV_SIGNAL
事件发生时,将_sigev_signo 指定的信号(A queued signal)_发送给指定的进程.
3.SIGEV_THREAD
事件发生时,内核会(在此进程内)以_sigev_notification_attributes_为线程属性创建一个线程，并且让它执行_sigev_notify_function_，传入_sigev_value_作为为一个参数.
sigev_signo
在_sigev_notify = SIGEV_SIGNAL_ 时使用,指定信号的种别(number).
sigev_value
在_sigev_notify = SIGEV_THREAD_ 时使用,作为_sigev_notify_function_ 的参数_._
union sigval
{
int sival_int;
void *sival_ptr;
}; (*sigev_notify_function)(union sigval)
函数指针(指向通知执行函数),在_sigev_notify = SIGEV_THREAD_ 时使用, 其他情况下置为NULL.
sigev_notify_attributes
指向线程属性的指针,在_sigev_notify = SIGEV_THREAD_ 时使用,指定创建线程的属性, 其他情况下置为NULL.
struct timespec
The
struct timespec
{
time_t tv_sec; /* Seconds */
long tv_nsec; /* Nanoseconds(纳秒:十亿分之一秒) */
};struct itimerspec
The _
struct itimerspec
{
struct timespec it_interval; /* Timer interval(timer循环时间间隔) */
struct timespec it_value; /* Initial expiration(timer初次到期时间间隔) */
};clockid_t
clockid_t is used for clock ID type in the clock and timer functions, 取值范围如下(前4个是POSIX定义的,灰色部分为Linux的扩展),
/* Identifier for system-wide realtime clock, Setting this clock requires appropriate privileges */
#define CLOCK_REALTIME 0
/* Monotonic system-wide clock, Clock that cannot be set and represents monotonic time since some unspecified starting point */
#define CLOCK_MONOTONIC 1
/* High-resolution timer from the CPU. (since Linux 2.6.12) */
#define CLOCK_PROCESS_CPUTIME_ID 2
/* Thread-specific CPU-time clock. (since Linux 2.6.12) */
#define CLOCK_THREAD_CPUTIME_ID 3
/* Monotonic system-wide clock, not adjusted for frequency scaling. */
#define CLOCK_MONOTONIC_RAW 4
/* Identifier for system-wide realtime clock, updated only on ticks. */
#define CLOCK_REALTIME_COARSE 5
/* Monotonic system-wide clock, updated only on ticks. */
#define CLOCK_MONOTONIC_COARSE 6CLOCK_REALTIME : 这种时钟表示的是绝对时间, 指的是从1970年1月1月0:00到目前经过多少秒, 相当于你的linux系统中显示的时间, 所以这个时间是可以更改的, 当系统的时钟源被改变，或者系统管理员重置了系统时间之后，这种类型的时钟可以得到相应的调整, 对设定为此类型的timer是有影响的.
CLOCK_MONOTONIC : 这种时钟表示的是相对时间, 其值对通过累积时钟节拍(嘀嗒)计算出来的, 不受时钟源等的影响, 从系统启动这一刻起开始计时, 如果你想计算出在一台计算机上不受重启的影响，两个事件发生的间隔时间的话，那么它将是最好的选择。
CLOCK_PROCESS_CPUTIME_ID : 测量调用进程(包括该进程内所有的线程)用户和系统消耗的总CPU时间.
CLOCK_THREAD_CPUTIME_ID : 测量调用线程消耗的CPU时间.
struct timeval
The _
struct timeval
{
time_t tv_sec; // Seconds(秒).
suseconds_t tv_usec; // Microseconds(微秒:千分之一毫秒).
};struct itimerval
The _
struct itimerval
{
struct timeval it_interval; /* Timer interval(timer循环时间间隔) */
struct timeval it_value; /* Initial expiration(timer初次到期时间间隔) */
};strcut tm
The _
struct tm
{
int tm_sec //Seconds [0,60]. 60 is used for leap seconds.
int tm_min //Minutes [0,59].
int tm_hour //Hour [0,23].
int tm_mday //Day of month [1,31].
int tm_mon //Month of year [0,11].
int tm_year //Years since 1900.
int tm_wday //Day of week [0,6] (Sunday =0).
int tm_yday //Day of year [0,365]. The number of days since January 1
int tm_isdst //Daylight Savings flag(夏时令)
};注意:
1)使用localtime等函数取得tm结构体,表示当前时间时, 年数要加1900,月数要加1;因为tm\_year是1900的偏移量,tm\_mon是从0开始计算的.
2)tm_isdst是夏时令的标志, 大于0表示时间使用了夏时令, 0表示未使用夏时令,小于0表示没有相关信息.
struct sockaddr
The
struct sockaddr
{
sa_family_t sa_family; //Address family.
char sa_data[14]; // Socket address (variable-length data).
};The sockaddr structure is used to define a socket address which is used in the _bind_(), _connect_(), _getpeername_(), _getsockname_(), _recvfrom_(), and _sendto_() functions.
struct sockaddr__in_
The _
typedef uint32_t in_addr_t; /* Internet address. */
struct in_addr
{
in_addr_t s_addr;
};
struct sockaddr_in
{
sa_family_t sin_family; //AF_INET.
in_port_t sin_port; //Port number(网络字节序).
struct in_addr sin_addr; //IP address(网络字节序).
};The sockaddr_in structure is used to store addresses for the Internet address family. Pointers to this type shall be cast by applications to struct sockaddr * for use with socket functions.
struct hostent
The _
struct hostent
{
char *h_name; //Official name of the host.
char **h_aliases; //主机的别名,可以有多个,最一个是空指针
int h_addrtype; //Address type.always AF_INET or AF_INET6 at present.
int h_length; //地址的长度(IPv4的长度为4字节).
char **h_addr_list; //IP地址,可以有多个,最后一个是空指针(网络字节序)
};
#define h_addr h_addr_list[0] /* for backward compatibility */
/* 注意事项
(1)h_aliases 和 h_addr_list 的用法见例子:http://www.cnblogs.com/LubinLew/p/Linux-gethostbyname.html
(2)h_addr_list中存储的IP地址格式为点分10进制,因为是网络字节序,不能用printf直接打印出来,需要使用inet_ntop函数来转换
*/Ip Protocol
/* Standard well-defined IP protocols. */
enum {
IPPROTO_IP = 0, /* Dummy protocol for TCP. */
IPPROTO_ICMP = 1, /* Internet Control Message Protocol. */
IPPROTO_IGMP = 2, /* Internet Group Management Protocol. */
IPPROTO_IPIP = 4, /* IPIP tunnels (older KA9Q tunnels use 94). */
IPPROTO_TCP = 6, /* Transmission Control Protocol. */
IPPROTO_EGP = 8, /* Exterior Gateway Protocol. */
IPPROTO_PUP = 12, /* PUP protocol. */
IPPROTO_UDP = 17, /* User Datagram Protocol. */
IPPROTO_IDP = 22, /* XNS IDP protocol. */
IPPROTO_TP = 29, /* SO Transport Protocol Class 4. */
IPPROTO_DCCP = 33, /* Datagram Congestion Control Protocol. */
IPPROTO_IPV6 = 41, /* IPv6 header. */
IPPROTO_RSVP = 46, /* Reservation Protocol. */
IPPROTO_GRE = 47, /* General Routing Encapsulation. */
IPPROTO_ESP = 50, /* encapsulating security payload. */
IPPROTO_AH = 51, /* authentication header. */
IPPROTO_MTP = 92, /* Multicast Transport Protocol. */
IPPROTO_BEETPH = 94, /* IP option pseudo header for BEET. */
IPPROTO_ENCAP = 98, /* Encapsulation Header. */
IPPROTO_PIM = 103, /* Protocol Independent Multicast. */
IPPROTO_COMP = 108, /* Compression Header Protocol. */
IPPROTO_SCTP = 132, /* Stream Control Transmission Protocol. */
IPPROTO_UDPLITE = 136, /* UDP-Lite protocol. */
IPPROTO_RAW = 255, /* Raw IP packets. */
IPPROTO_MAX
};struct addrinfo
The _
#include
#include
#include
/* ======================Types of sockets====================== */
enum __socket_type {
SOCK_STREAM = 1, /* Sequenced, reliable, connection-based byte streams. */
SOCK_DGRAM = 2, /* Connectionless, unreliable datagrams of fixed maximum length. */
SOCK_RAW = 3, /* Raw protocol interface. */
SOCK_RDM = 4, /* Reliably-delivered messages. */
SOCK_SEQPACKET = 5, /* Sequenced, reliable, connection-based,datagrams of fixed maximum length. */
SOCK_DCCP = 6, /* Datagram Congestion Control Protocol. */
SOCK_PACKET = 10, /* Linux specific way of getting packets at the dev level. For writing rarp and other similar things on the user level. */
/* Flags to be ORed into the type parameter of socket and socketpair and used for the flags parameter of paccept. */
SOCK_CLOEXEC = 02000000, /* Atomically set close-on-exec flag for the new descriptor(s). */
SOCK_NONBLOCK = 00004000 /* Atomically mark descriptor(s) as non-blocking. */
};
/* ============Protocol families(只列出常用几个)================= */
#define PF_UNSPEC 0 /* Unspecified. */
#define PF_LOCAL 1 /* Local to host (pipes and file-domain). */
#define PF_INET 2 /* IP protocol family. */
#define PF_IPX 4 /* Novell Internet Protocol. */
#define PF_APPLETALK 5 /* Appletalk DDP. */
#define PF_INET6 10 /* IP version 6. */
#define PF_TIPC 30 /* TIPC sockets. */
#define PF_BLUETOOTH 31 /* Bluetooth sockets. */
/* ==============Address families(只列出常用几个)================= */
#define AF_UNSPEC PF_UNSPEC
#define AF_LOCAL PF_LOCAL
#define AF_UNIX PF_UNIX
#define AF_FILE PF_FILE
#define AF_INET PF_INET
#define AF_IPX PF_IPX
#define AF_APPLETALK PF_APPLETALK
#define AF_INET6 PF_INET6
#define AF_ROSE PF_ROSE
#define AF_NETLINK PF_NETLINK
#define AF_TIPC PF_TIPC
#define AF_BLUETOOTH PF_BLUETOOTH
/* ====Possible values for `ai_flags' field in `addrinfo' structure.===== */
#define AI_PASSIVE 0x0001 /* Socket address is intended for `bind'. */
#define AI_CANONNAME 0x0002 /* Request for canonical name. */
#define AI_NUMERICHOST 0x0004 /* Don't use name resolution. */
#define AI_V4MAPPED 0x0008 /* IPv4 mapped addresses are acceptable. */
#define AI_ALL 0x0010 /* Return IPv4 mapped and IPv6 addresses. */
#define AI_ADDRCONFIG 0x0020 /* Use configuration of this host to choose returned address type. */
#ifdef __USE_GNU
#define AI_IDN 0x0040 /* IDN encode input (assuming it is encoded
in the current locale's character set) before looking it up. */
#define AI_CANONIDN 0x0080 /* Translate canonical name from IDN format. */
#define AI_IDN_ALLOW_UNASSIGNED 0x0100 /* Don't reject unassigned Unicode code points. */
#define AI_IDN_USE_STD3_ASCII_RULES 0x0200 /* Validate strings according to STD3 rules. */
#endif
#define AI_NUMERICSERV 0x0400 /* Don't use name resolution. */
/* =======================struct addrinfo======================= */
struct addrinfo {
int ai_flags; /* 附加选项,多个选项可以使用或操作结合 */
int ai_family; /* 指定返回地址的协议簇,取值范围:AF_INET(IPv4)、AF_INET6(IPv6)、AF_UNSPEC(IPv4 and IPv6) */
int ai_socktype; /* enum __socket_type 类型，设置为0表示任意类型 */
int ai_protocol; /* 协议类型，设置为0表示任意类型,具体见上一节的 Ip Protocol */
socklen_t ai_addrlen; /* socket address 的长度 */
struct sockaddr *ai_addr; /* socket address 的地址 */
char *ai_canonname; /* Canonical name of service location. */
struct addrinfo *ai_next; /* 指向下一条信息,因为可能返回多个地址 */
};