What does the -ObjC linker flag do?

Question

I have an app that works with and without the linker flag. However, without the linker flag, I get a very different behaviour when adding data to a view.

bensarz, you get a _different_ behaviour without the linker flag... What does that mean?? Different how? — Adil Hussain, Jun 20 '17 at 13:12

score 164 · Accepted Answer · answered Jul 08 '11 at 20:18

164

This flag causes the linker to load every object file in the library that defines an Objective-C class or category. While this option will typically result in a larger executable (due to additional object code loaded into the application), it will allow the successful creation of effective Objective-C static libraries that contain categories on existing classes.

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answered Jul 08 '11 at 20:18

sergio

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Great! Thank you. Is this caused by the fact that we are using GCC 4.2 as a compiler? Would using LLVM GCC 4.2 or LLVM Compiler 2.0 solve the problem? Or am I mixing up stuff that shouldn't be mixed? – bsarrazin Jul 08 '11 at 20:25
I think that the behavior is the same with both compilers (besides, I don't know if there are 2 different linkers)... – sergio Jul 08 '11 at 20:35
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Does this mean that you would never need `-ObjC` in anything other than a library / SDK? I.e. you should never need to use it in an actual app target? – Robert Feb 24 '14 at 15:20
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No, this means you need -ObjC in any project implementing a library that has a category or embedded framework in it – arc4randall Jan 08 '16 at 00:20
Just found this out the hard way! – Alexandre G Feb 09 '16 at 08:07

What does the -ObjC linker flag do?

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