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/GT (Support Fiber-Safe Thread-Local Storage)
This option supports fiber safety for data allocated using static thread-local storage, that is, data allocated with __declspec(thread).
Data declared with __declspec(thread) is referenced through a thread-local storage (TLS) array. The TLS array is an array of addresses that the system maintains for each thread. Each address in this array gives the location of thread-local storage data.
A fiber is a lightweight object that consists of a stack and a register context and can be scheduled on various threads. A fiber can run on any thread. Because a fiber may get swapped out and restarted later on a different thread, the address of the TLS array must not be cached or optimized as a common subexpression across a function call (see the /Og option for details). /GT prevents such optimizations.
To set this compiler option in the Visual Studio development environment
- Open the project's Property Pages dialog box. For details, see Setting Visual C++ Project Properties.
- Click the C/C++ folder.
- Click the Optimization property page.
- Modify the Enable Fiber-safe Optimizations property.
To set this compiler option programmatically