我尝试编译以下代码： 这是server.h代码（https://codeshare.io/an3XW4）
///////////////HEADER FILES///////////////
#include <pthread.h>
#include "Server.h"
///////////////FUNCTIONS///////////////
/*Thread Main Function
Variable Definition:
-- thread_arguments: arguments which thread should be used
Return Value: NULL
*/
void *threadMain(void *thread_arguments){
int client_socket; //socket descriptor for client
//Guarantees that thread resources are deallocated upon return
pthread_detach(pthread_self());
//Pass the arguments
client_socket = ((THREAD_ARGUMENTS*)thread_arguments)->client_socket;
//Deallocate memory for argument
free(thread_arguments);
//Handle the client request
handleClientRequest(client_socket);
return (NULL);
}
这是TIMEUTILITY.C，我对C不太了解，我是用Java和其他更高级语言的程序员。
///////////////HEADER FILES///////////////
#include <sys/stat.h>
#include <time.h>
#include "Server.h"
///////////////FUNCTIONS///////////////
/*Set Timer Function
Variable Definition:
-- timer: itimerval structure
-- type: timer type
-- interval_sec: it_interval seconds
-- interval_usec: it_interval microseconds
-- value_sec: it_value seconds
-- value_usec: it_value microseconds
Return value: NULL
*/
void setTimer( struct itimerval timer,
int type,
u_int32 interval_sec,
u_int32 interval_usec,
u_int32 value_sec,
u_int32 value_usec){
//Set the time out value
timer.it_interval.tv_sec = interval_sec;
timer.it_interval.tv_usec = interval_usec;
//Set the first time out value
timer.it_value.tv_sec = value_sec;
timer.it_value.tv_usec = value_usec;
//Set the timer
if (setitimer(type, &timer, NULL) != 0){
dieWithSystemMessage("setitimer() failed");
}
return;
}
/*Get GMT Time Function (including System time and File time)
Variable Definition:
-- url: the request url except domain name and port number
-- signal_value: signal that decide which kind of time needed
Return value: tm struct in GMT Format
*/
struct tm *getTimeInGMTFormat(char *url, int signal_value){
struct stat file_information; //file information sstructure
time_t t; //time structure
//signal_value equals to 0, get the system current time
if (!signal_value){
time(&t);
}
//signal_value not equals to 0, get the file time(Create time, Modify time, Access time...)
else if (stat(url, &file_information) != -1){
switch(signal_value){
//signal_value is 1, get the file create time
case 1: t = file_information.st_atime; break;
//signal_value is 2, get the file modify time
case 2: t = file_information.st_mtime; break;
//signal_value is others
default: break;
}
}
//Cannot find the file information
else{
dieWithUserMessage("stat() failed(cannot find the file information), file name", url);
}
return gmtime(&t);
}
/*Convert Time Format to a string
Variable Definition:
-- gmt_time: tm struct in GMT format
-- signal_value: signal that decide which time format to convert
Return value: time string in GMT format
*/
char *convertTimeFormat(struct tm *gmt_time, int signal_value){
char *gmt_time_string = (char*)malloc(sizeof(char) * (TIME_SIZE + 1)); //time in GMT format string
//According to the signal_value, convert time to different format
switch(signal_value){
case 1:
strftime(gmt_time_string, TIME_SIZE, "%a, %d %b %Y %H:%M:%S GMT", gmt_time);
break;
case 2:
strftime(gmt_time_string, TIME_SIZE, "%A, %d-%b-%y %H:%M:%S GMT", gmt_time);
break;
case 3:
gmt_time_string = asctime(gmt_time);
gmt_time_string[strlen(gmt_time_string) - 1] = '\0';
break;
default:
break;
}
return gmt_time_string;
}
/*Compare the If-Modified-Since field and Last-Modified field Function
Variable Definition:
-- url: the request url except domain name and port number
-- modified_time_string: If-Modified-Since field value
Return Value: if If-Modified-Since field equals to Last-Modified field, return 1; else return 0
*/
bool compareModifiedTime(char *url, char *modified_time_string){
struct tm *file_modified_time = getTimeInGMTFormat(url, 2); //tm struct with the file last modified time
int i; //counter
//Test the modified time is equal(three format: RFC 1123, RFC 1036, and ANSI C's format)
for (i = 1; i < NUMBER_SIZE; i++){
if (strcmp(modified_time_string, convertTimeFormat(file_modified_time, i)) == 0){
return true;
}
}
return false;
}
但是当我尝试使用g ++（C ++编译器）（代码本机用C语言编写）进行编译时，出现一个奇怪的错误，有人知道为什么吗？这是Thread.C的完整代码
/home/justin/Documents/dcn_streaming_video/server/Thread.c:23: multiple definition of `client_rtcp_port'
TimeUtility.o:/home/justin/Documents/dcn_streaming_video/server/TimeUtility.c:36: first defined here
Thread.o: In function `threadMain(void*)':
/home/justin/Documents/dcn_streaming_video/server/Thread.c:23: multiple definition of `client_rtp_port'
TimeUtility.o:/home/justin/Documents/dcn_streaming_video/server/TimeUtility.c:36: first defined here
Thread.o: In function `threadMain(void*)':
/home/justin/Documents/dcn_streaming_video/server/Thread.c:27: multiple definition of `range_end'
TimeUtility.o:/home/justin/Documents/dcn_streaming_video/server/TimeUtility.c:37: first defined here
Thread.o: In function `threadMain(void*)':
/home/justin/Documents/dcn_streaming_video/server/Thread.c:27: multiple definition of `range_start'
TimeUtility.o:/home/justin/Documents/dcn_streaming_video/server/TimeUtility.c:37: first defined here
Thread.o: In function `threadMain(void*)':
/home/justin/Documents/dcn_streaming_video/server/Thread.c:27: multiple definition of `status'
TimeUtility.o:/home/justin/Documents/dcn_streaming_video/server/TimeUtility.c:39: first defined here
Thread.o: In function `threadMain(void*)':
/home/justin/Documents/dcn_streaming_video/server/Thread.c:31: multiple definition of `session_id'
TimeUtility.o:/home/justin/Documents/dcn_streaming_video/server/TimeUtility.c:39: first defined here
Thread.o: In function `threadMain(void*)':
/home/justin/Documents/dcn_streaming_video/server/Thread.c:33: multiple definition of `rtp_address'
TimeUtility.o:/home/justin/Documents/dcn_streaming_video/server/TimeUtility.c:40: first defined here
Thread.o:(.bss+0x50): multiple definition of `protocol_method'
TimeUtility.o:/home/justin/Documents/dcn_streaming_video/server/TimeUtility.c:55: first defined here
Thread.o:(.bss+0x60): multiple definition of `protocol_type'
TimeUtility.o:/home/justin/Documents/dcn_streaming_video/server/TimeUtility.c:60: first defined here
答案 0 :(得分：-1)
正如其他人指出的那样，我没有看到完整的源代码，特别是Server.h，它可能不使用多个包含保护（即一次ifdef或pragma顶层）。