10、Linux环境下的##连接符与args...混合使用
前面【1】中叙述了#,##的使用方法，【2】中叙述了va_list的使用方法。
【1】 http://www.cnblogs.com/mydomain/archive/2010/09/25/1834917.html
【2】 http://www.cnblogs.com/mydomain/archive/2010/12/06/1898187.html
在Linux下，还有一种使用形式，如下：
#define NO_DATA(fmt, args...) \
{\
fprintf(stdout, fmt, ##args);\
}
int main(int argc, char* argv[])
{
char* pc = new char[14];
strncpy(pc, "1234", 5);
NO_DATA("%d %s", 2, pc);
delete[] pc;
return 1;
}
output 是2 1234。
11、strtok
char *strtok(char *s, const char *delim);
The strtok() function parses a string into a sequence of tokens. On the first call to strtok() the string to be parsed should be specified in s. In each subsequent call that should parse the same string, s should be NULL.
只要在s字符串中发现与字符集delim中相符的任一个字符，则将s字符串中该字符换成a null character。也就是说，在调用的过程中，字串s被改变了。
该函数返回从s开头开始的一个个被delim字符集中字符分割的串。当没有被分割的串时则返回NULL。
token = strtok( string, seps );
while( token != NULL )
{
/* While there are tokens in "string" */
printf( " %s\n", token );
/* Get next token: */
token = strtok( NULL, seps );
}
【1】 http://linux.die.net/man/3/strtok
【2】 http://baike.baidu.com/view/1028553.htm
12、strdup
#include <string.h>
char *strdup(const char *s);
The strdup() function returns a pointer to a new string which is a duplicate of the string s.所需空间由malloc()分配，且可以(必须)由free()释放。
char *s="Golden Global View";
char *d;
d=strdup(s);
printf("%s",d);
free(d);
【1】 http://baike.baidu.com/view/1028541.htm
【2】 http://linux.die.net/man/3/strdup
12、inet_ntop
const char *inet_ntop(int af, const void *src,char *dst, socklen_t cnt);
converts the network address structure src in the af address family into a character string, which is copied to a character buffer dst, which is cnt bytes long.
int inet_pton(int af, const char *src, void *dst);
This function converts the character string src into a network address structure in the af address family, then copies the network address structure to dst.
将该地址转换为in_addr的结构体，并复制在*dst中。
char ip_dot_dec[20];
struct in_addr na;
cout << "Input IP addr: ";
cin >> ip_dot_dec;
inet_pton(AF_INET, ip_dot_dec, (void *)&na);
cout << "inet_pton: 0x" << hex << na.s_addr << endl;
inet_ntop(AF_INET, (void *)&na, ip_dot_dec, 16);
cout << "inet_ntop: " << ip_dot_dec << endl;
【1】 http://linux.die.net/man/3/inet_ntop
【2】 百度百科
13、socket
int socket(int domain, int type, int protocol);
socket() creates an endpoint for communication and returns a descriptor.
On success, a file descriptor for the new socket is returned. On error, -1 is returned, and errno is set appropriately.
int sock_fd = socket(PF_INET, SOCK_STREAM, 0);
【1】 http://linux.die.net/man/2/socket
14、bind
int bind(int sockfd, const struct sockaddr *my_addr, socklen_t addrlen);
bind() gives the socket sockfd the local address my_addr. my_addr is addrlen bytes long. Traditionally, this is called "assigning a name to a socket."
On success, zero is returned. On error, -1 is returned, and errno is set appropriately.
int sfd;
struct sockaddr_un addr;
sfd = socket(AF_UNIX, SOCK_STREAM, 0);
if (sfd == -1)
{
perror("socket");
exit(EXIT_FAILURE);
}
/* Clear structure */
memset(&addr, 0, sizeof(struct sockaddr_un));
addr.sun_family = AF_UNIX;
strncpy(addr.sun_path, MY_SOCK_PATH, sizeof(addr.sun_path) - 1);
if (bind(sfd, (struct sockaddr *) &addr, sizeof(struct sockaddr_un)) == -1)
{
perror("bind");
exit(EXIT_FAILURE);
}
【1】 http://linux.die.net/man/2/bind
15、listen
int listen(int sockfd, int backlog);
The listen() call applies only to sockets of type SOCK_STREAM or SOCK_SEQPACKET.
The backlog parameter defines the maximum length the queue of pending connections may grow to.
int ret = listen(_socket_fd, 32);
【1】 http://linux.die.net/man/2/listen
16、accept
int accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen);
创建新的套接字，并返回该套接字的文件描述符。新创建的套接字用于服务器与客户机的通信，而原来的套接字仍然处于监听状态。
【1】 http://linux.die.net/man/2/accept
【2】 http://baike.baidu.com/view/521407.htm
17、connect
int connect(int sockfd, const struct sockaddr *serv_addr, socklen_t addrlen);
用来将参数sockfd 的socket 连至参数serv_addr 指定的网络地址。
【1】 http://linux.die.net/man/2/connect
【2】 http://baike.baidu.com/view/888434.htm
18、getpeername
int getpeername(int s, struct sockaddr *name, socklen_t *namelen);
getpeername() returns the name of the peer connected to socket s. 也就是获取socket的对方地址。
getsockname() returns the current name for the specified socket.
【1】 http://baike.baidu.com/view/569194.html
【2】 http://linux.die.net/man/2/getsockname
19、stat
返回文件的信息
int stat(const char *path, struct stat *buf);
These functions return information about a file.
On success, zero is returned. On error, -1 is returned, and errno is set appropriately.
【1】 http://linux.die.net/man/2/stat
20、strftime
size_t strftime(char *s, size_t max, const char *format, const struct tm *tm);
The strftime() function formats the broken-down time tm according to the format specification format and places the result in the character array s of size max.
【1】 http://baike.baidu.com/view/1284677.htm
【2】 http://linux.die.net/man/3/strftime
tm 多是用localtime函数转换过的本地时间。