printf
Ситуация такая: нужно записывать в лог инфу из нескольких потоков, безопасно ли использовать для этих целей обычный printf(), если редиректнуть stdout на какой-либо файл? Если короче, то является ли printf() thread-safe функцией?
Заранее спасибо.
Заранее спасибо.
Иногда помогает заглянуть в хелп. Это зависит от библиотеки.
LIBC.LIB Single thread static library, retail version
LIBCMT.LIB Multithread static library, retail version
MSVCRT.LIB Import library for MSVCRT.DLL, retail version
LIBC.LIB Single thread static library, retail version
LIBCMT.LIB Multithread static library, retail version
MSVCRT.LIB Import library for MSVCRT.DLL, retail version
This Rogue Wave implementation of iostreams and locales is Multithread-Safe: Level 2. All public and protected functions are reentrant, and there is protection against multiple threads trying to modify static and global data. The preferred method of protection is mutex locks; the library also locks an object before writing to it. The developer is not required to explicitly lock or unlock a class object, whether static, global, or local, in order to perform a single operation on the object.
This means that iostream objects, with the exception of stream buffers, can be shared between threads of execution using a simple mutex object without explicit locking. The locking mechanism is enforced at the stream level. Therefore, all operations carried out on the stream are multithread safe, including the following:
Thread 1: Thread 2:
cout << "Thread 1" << endl; cout << " Thread 2" << endl;
This means that iostream objects, with the exception of stream buffers, can be shared between threads of execution using a simple mutex object without explicit locking. The locking mechanism is enforced at the stream level. Therefore, all operations carried out on the stream are multithread safe, including the following:
Thread 1: Thread 2:
cout << "Thread 1" << endl; cout << " Thread 2" << endl;
Так с printf() такая хрень прокатит? Я так понял, что это только для iostream-объектов?
Посмотри Example на _beginthread() там в потоках printf() используется без всяких синхронизаций.