/Ob (In-line Function Expansion)
| Overview | How Do I | Compiler Options
Feature Only in Professional and Enterprise Editions Code optimization is supported only in Visual C++ Professional and Enterprise Editions. For more information, see .
The In-line Function Expansion (/Obn)**options control inline expansion of functions, where n is one of the following:
| Command Line | Project Settings | Description |
| /Ob0 | Disable | Disables inline expansion (default) |
| /Ob1 | Only __inline | Expands only functions marked as inline or __inline or, in a C++ member function, defined within a class declaration (default with /O1, /O2, and /Ox) |
| /Ob2 | Any Suitable | Expands functions marked as inline or __inline and any other function that the compiler chooses (expansion occurs at compiler discretion—often referred to as “auto-inlining”) |
(To find this option in the development environment, click Settings on the Project menu. Then click the C/C++ tab, and click Optimizations in the Category box.)
The compiler treats the inline expansion options and keywords as suggestions. There is no guarantee that functions will be inlined. You cannot force the compiler to inline a particular function.
You can also use #pragma auto_inline to exclude functions from being considered as candidates for inline expansion. Also see #pragma intrinsic.