Synchronizing UART TX

if I do use a binary semaphore and initialize in the ctor sem = xSemaphoreCreateBinary();, I suspect xSemaphoreTake causes the current task to be blocked. Perhaps I was looking from a mutex perspective that gives exclusive rights to the said task rather than blocking it.

So maybe I want something like this but is this the preferred approach?

    template<typename... Args>
    void Print(const char* format, Args... args)	
	       char buffer[100] = {0};

	       std::snprintf(buffer, sizeof(buffer), format, args...);
	       std::strcat(buffer, "\r\n");
	       size_t length = strlen(buffer);

	      TXInterrupt(reinterpret_cast<T*> (buffer), length);

          xSemaphoreTake(sem, portMAX_DELAY); // "wait" till the TX transmission is done