/Ox (Full Optimization)

The latest version of this topic can be found at -Ox (Full Optimization).

The /Ox compiler option produces code that favors execution speed over smaller size.

Syntax

/Ox  

Remarks

Specifying the /Ox compiler option is the same as using the following options:

• /Ob (Inline Function Expansion), where the option parameter is 2 (/Ob2)

• /Og (Global Optimizations)

• /Oi (Generate Intrinsic Functions)

• /Ot (Favor Fast Code)

• /Oy (Frame-Pointer Omission)

/Ox is mutually exclusive from:

• /O1 (Minimize Size)

• /O2 (Maximize Speed)

• /Od (Disable (Debug))

The /Ox compiler option also enables the Named Return Value optimization, which eliminates the copy constructor and destructor of a stack based return value. For more information, see /O1, /O2 (Minimize Size, Maximize Speed).

You can cancel out the /Ox compiler option if you specify /Oxs, which combines the /Ox compiler option with /Os (Favor Small Code). The combined options favor smaller code size.

In general, specify /O2 (Maximize Speed) instead of /Ox, and /O1 (Minimize Size) instead of /Oxs.

To set this compiler option in the Visual Studio development environment

1. Open the project's Property Pages dialog box. For details, see How to: Open Project Property Pages.

2. Click the C/C++ folder.

3. Click the Optimization property page.

4. Modify the Optimization property.

To set this compiler option programmatically

• See Optimization.

See Also

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