/Oy (Frame-Pointer Omission)

Suppresses creation of frame pointers on the call stack.

Syntax

/Oy[-]

Remarks

This option speeds function calls, because no frame pointers need to be set up and removed. It also frees one more register for general usage.

/Oy enables frame-pointer omission and /Oy- disables omission. In x64 compilers, /Oy and /Oy- are not available.

If your code requires frame-based addressing, you can specify the /Oy- option after the /Ox option or use optimize with the "y" and off arguments to gain maximum optimization with frame-based addressing. The compiler detects most situations where frame-based addressing is required (for instance, with the _alloca and setjmp functions and with structured exception handling).

The /Ox (Enable Most Speed Optimizations) and /O1, /O2 (Minimize Size, Maximize Speed) options imply /Oy. Specifying /Oy- after the /Ox, /O1, or /O2 option disables /Oy, whether it is explicit or implied.

The /Oy compiler option makes using the debugger more difficult because the compiler suppresses frame pointer information. If you specify a debug compiler option (/Z7, /Zi, /ZI), we recommend that you specify the /Oy- option after any other optimization compiler options.

To set this compiler option in the Visual Studio development environment

  1. Open the project's Property Pages dialog box. For details, see Working with Project Properties.

  2. Select the Configuration Properties > C/C++ > Optimization property page.

  3. Modify the Omit Frame Pointers property. This property adds or removes only the /Oy option. If you want to add the /Oy- option, select the Command Line property page and modify Additional options.

To set this compiler option programmatically

See Also

/O Options (Optimize Code)
Compiler Options
Setting Compiler Options