我正在编写一个 C 解决方案来解决餐馆野人问题中的某些变量。现在，我创建了线程，每个线程都会得到一个 FILE* 指向相同的调试文件；在线程内部，我使用 fprintf() 进行一些打印操作。打印语句没有受到任何互斥等保护。
我没有观察到调试文件中的任何交错行为；看起来它是线程安全的，尽管我在网上没有找到明确的声明。
我所看到的是以下内容：
1. 在 Unix 中，fprintf 是线程安全的。 2. 使用 c++11 编译器需要让 fprintf 线程安全。
我之所以问这个问题，是因为这是一项大学任务，虽然它可以工作，但我仍然怀疑在另一台基于 Windows 的计算机上，由于上述不确定性，程序可能会出现问题。
我将附上线程代码，以便您查看打印是否受到保护。
我没有观察到调试文件中的任何交错行为；看起来它是线程安全的，尽管我在网上没有找到明确的声明。
我所看到的是以下内容：
1. 在 Unix 中，fprintf 是线程安全的。 2. 使用 c++11 编译器需要让 fprintf 线程安全。
我之所以问这个问题，是因为这是一项大学任务，虽然它可以工作，但我仍然怀疑在另一台基于 Windows 的计算机上，由于上述不确定性，程序可能会出现问题。
我将附上线程代码，以便您查看打印是否受到保护。
DWORD WINAPI RoomateThread(LPVOID lpParam) {
/*=================================================
"RoomateThread" this is the roomate thread handler function where
the thread logic is implemented
Input: 1. lpParam holds a roomate, runtime and pointers to both files
Output: 1. return an DWORD value {0}->Success {-1}->Failure
2. A code telling if the run was successful (debug file)
A roommate follows this logic after wake up:
1. If there are clothes available in the closet:
a. Wait for mutex to be available, take it
b. Check if the basket is full
b.1. If it is - start the machine and wait for it to finish
c. Throw an item in the basket
d. release mutex
2. If the closet is empty, wait for laundry_is_empty signal, then goto (1.a)
=================================================*/
/*variable declerations*/
DWORD wait_res, delta;
BOOL release_res;
LONG previous_count;
roomate_thread *elem;
elem = (roomate_thread*)lpParam;
/*thread logic*/
while (TRUE) {
/*calculate the delta between the total run time and the time the roomate had run so far*/
delta = total_time - elem->run_time;
/*wait until the minimum between period Ti and delta*/
Sleep(min(elem->roomate->run_time,delta));
fprintf(elem->debug, "RoomateThread(): Line %d, roomate %d: slept for %d mili sec, starting...\n", __LINE__, elem->roomate->roomate_id, min(elem->roomate->run_time, delta));
/*as instructed, each roomate is active since the wakeup*/
fprintf(elem->report, "\nRoomate %d active", elem->roomate->roomate_id);
/*update the element total run time since start*/
elem->run_time = elem->run_time + min(elem->roomate->run_time, delta);
if (time_to_stop < elem->run_time) {
/*if the element total run time is bigger then the global variable update the global*/
time_to_stop = elem->run_time;
}
/*its time to close the thread properly*/
if (time_to_stop == total_time) {
/*if the laundry basket has clothes in it, and the roomate run as much as the total time
activate rhe robot once more and exit*/
if (elem->run_time == total_time && items_in_laundry!=0) {
release_res = ReleaseSemaphore(
laundry_is_full,
1,
&previous_count);
if (release_res == FALSE) {
fprintf(elem->debug, "MachineThread(): Line %d, released semaphore 'laundry_is_full' failed\nthe last error is: 0X%x\n", __LINE__, GetLastError());
return FAILURE;
}
}
break;
}
/*checks that the roomate has clothes in the closet to continue*/
if (elem->roomate->clothes_in_laundry < elem->roomate->clothes-1) {/*roomate has clothes available*/
fprintf(elem->debug, "RoomateThread(): Line %d, roomate id= %d, number of dirty clothes=%d, number of total dirty clothes=%d\n",__LINE__, elem->roomate->roomate_id, elem->roomate->clothes_in_laundry, items_in_laundry);
}
// It's empty:
else {
/*waits until one of the roomates will activate the robot, cause there is no clothes in the roomate closet*/
fprintf(elem->debug, "DAVIDS roomate %d have no clothes, waiting!!!\n", elem->roomate->roomate_id);
elem->roomate->closet_empty = TRUE;
/*Wait until the machine is done*/
wait_res = WaitForSingleObject(laundry_is_empty, INFINITE);
fprintf(elem->debug, "RoomateThread(): Line %d, roomate %d have clothes,finish waiting!!!\n",__LINE__, elem->roomate->roomate_id);
if (wait_res != WAIT_OBJECT_0) {
fprintf(elem->debug, "RoomateThread() error: Line %d, waiting for sempahore 'laundry_is_empty' failed\nthe last error is: 0X%x\n", __LINE__,GetLastError());
return FAILURE;
}
fprintf(elem->debug, "RoomateThread(): Line %d, laundry_is_empty semaphore aquired , roomate: %d\n", __LINE__,elem->roomate->roomate_id);
}
/* Wait for mutex (machine start and clothes add "rights")*/
wait_res = WaitForSingleObject(mutex, INFINITE);
if (wait_res != WAIT_OBJECT_0) {
fprintf(elem->debug, "RoomateThread() error: Line %d, waiting for 'mutex' failed\nthe last error is: 0X%x\n", __LINE__,GetLastError());
return FAILURE;
}
fprintf(elem->debug, "RoomateThread(): Line %d, mutex aquired , roomate: %d\n", __LINE__, elem->roomate->roomate_id);
fprintf(elem->debug, "RoomateThread(): Line 200, mutex aquired , roomate: %d\n",elem->roomate->roomate_id);
/*Check if basket it full*/
if (items_in_laundry == total_items) {
/*Start Machine*/
release_res = ReleaseSemaphore(
laundry_is_full,
1,
&previous_count);
if (release_res == FALSE) {
fprintf(elem->debug, "MachineThread(): Line %d, released semaphore 'laundry_is_empty' failed\nthe last error is: 0X%x\n", __LINE__, GetLastError());
return FAILURE;
}
fprintf(elem->debug, "RoomateThread(): Line 210, released semaphore 'laundry_is_full' last count is: %ld\n", previous_count);
/*Wait for it to finish*/
wait_res = WaitForSingleObject(laundry_is_empty, INFINITE);
if (wait_res != WAIT_OBJECT_0) {
fprintf(elem->debug, "RoomateThread() error: Line %d, waiting for sempahore 'laundry_is_empty' failed\nthe last error is: 0X%x\n", __LINE__, GetLastError());
return FAILURE;
}
items_in_laundry = 0;
}
/*Throw in a dirty cloth*/
elem->roomate->clothes_in_laundry++;
items_in_laundry++;
/*Release the mutex*/
release_res = ReleaseMutex(mutex);
if (release_res == FALSE) {
fprintf(elem->debug, "RoomateThread(): Line %d, released 'mutex' failed\nthe last error is: 0X%x\n", __LINE__, GetLastError());
return FAILURE;
}
fprintf(elem->debug, "RoomateThread(): Line %d, mutex released , roomate: %d\n", __LINE__, elem->roomate->roomate_id);
}
fprintf(elem->debug, "RoomateThread(): Line %d, thread of roomate %d ended\n", __LINE__, elem->roomate->roomate_id);
return SUCSSES;
}
只是再次提醒，这需要在Windows上使用Visual 2015运行。
非常感谢您的帮助！！！
**如果您需要更多的代码，我可以添加，尽管其余部分对所问的问题没有太多信息。