# Lower -o argument in expression

**URL:** <https://forums.kodeco.com/t/lower-o-argument-in-expression/33316>\
**Category:** Advanced Apple Debugging\
**Created:** [August 15, 2017, 8:03pm UTC](https://forums.kodeco.com/t/lower-o-argument-in-expression/33316 "2017-08-15T20:03:06Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![yasroslav](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/yasroslav/32/81494_2.png) [@yasroslav](https://forums.kodeco.com/u/yasroslav)\
**Post date:** [August 15, 2017, 8:03pm UTC](https://forums.kodeco.com/t/lower-o-argument-in-expression/33316/1 "2017-08-15T20:03:06Z")

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While rereading the book i’ve mention such line  
`ex -l swift -o -- unsafeBitCast(0x14bdd9b50, to: NSObject.self)`  
Here’s lower case -o option in the line. I haven’t found any description about such option in the book neither haven’t find any information in lldb help.  
@lolgrep could you please explain what’s the difference between this option and “-O” options in expression cmd?

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**Author:** ![lolgrep](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/lolgrep/32/106950_2.png) [@lolgrep](https://forums.kodeco.com/u/lolgrep)\
**Post date:** [August 26, 2017, 7:24pm UTC](https://forums.kodeco.com/t/lower-o-argument-in-expression/33316/2 "2017-08-26T19:24:04Z")

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@yasroslav,  
Technically, that would be a typo, but LLDB will translate a lower case `o` to `--object-description` (though I don’t know where in the source from LLDB this occurs [GitHub - llvm-mirror/lldb: Project moved to: https://github.com/llvm/llvm-project](https://github.com/llvm-mirror/lldb), also might be in the Swift LLDB repo…) when evaluating the expression.

You can verify by taking an address which points to a valid NSObject and trying with and without the `--object-description` option while in the Objective-C context and you can see that a lower case `o` will still produce the `description` or `debugDescription` of the memory address

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**Author:** ![system](https://s3.amazonaws.com/cdn.raywenderlich.com/community/forum-assets/noun-game-ghost-878668.png) [@system](https://forums.kodeco.com/u/system)\
**Post date:** [January 29, 2018, 12:03pm UTC](https://forums.kodeco.com/t/lower-o-argument-in-expression/33316/3 "2018-01-29T12:03:18Z")

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Closed on January 29, 2018, 12:03pm UTC

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