[wwiiol]

I'm working with semaphores and threads (semaphore.h and pthread.h).
If i try to compile blah.c from the command line
gcc blah.c -lpthread -lrt

I get the the error in the subject. Xcode compiles but gives me alot of errors from sem_wait().

I have tried reinstalling Xcode but that didn't help.

Any help would be appreciated ALOT.


[edit] I have the current xcode version (1.5).

[Angus_D]

That's because there is no librt? And libpthread is just a symlink to libSystem (which is linked automatically), so that's not needed either.

What do you getif you don't specify those libraries at all?

[wwiiol]

It compiles but i get errors from sem_wait() when I run it.

[Angus_D]

You get errors? Say it ain't true.

[wwiiol]

Anyone have constructive help?

[Chuckit]

If you want a good, specific answer, ask a good, specific question. How are we supposed to troubleshoot "I get errors"? There's no information about what kind of errors (Does it make the Quark robot come out and zap everything?) or any sample code for us to find problems with.

Are you using unnamed semaphores? MacOS X doesn't support unnamed semaphores, but it does support named semaphores. Use Google to get some more info and sample code.

[Chuckit]

I didn't think Mac OS X even had the APIs for unnamed semaphores (meaning it wouldn't be possible to compile an app that uses them).

[wwiiol]

The soruce file has nothing to do with it

I type in "gcc blah.c -lrt" at the command prompt.
I get this: "ld: can't locate file for: -lrt"

I can't be any more specific than this.

I believe I'm missing a file or something is not linked properly.

[wadesworld]

Originally posted by wwiiol:
The soruce file has nothing to do with it

I type in "gcc blah.c -lrt" at the command prompt.
I get this: "ld: can't locate file for: -lrt"

I can't be any more specific than this.

I believe I'm missing a file or something is not linked properly.

Well, if you're going to try to link to a library, you should make sure that the library exists.

There's no "librt.a" on OS X.

I don't know where you got the idea you needed such a lib, but it looks like the instructions were wrong.

Post the errors you get when you run it without attempting to link to libraries.

Wade

[Angus_D]

Originally posted by wwiiol:
The soruce file has nothing to do with it

Uh, sorry... You're compiling source code, and having problems, so how exactly is the source nothing to do with it? It's everything to do with it.

I type in "gcc blah.c -lrt" at the command prompt.
I get this: "ld: can't locate file for: -lrt"

And as I already said in the first reply way up there, there is no librt on OS X by default. Kicking and screaming won't magically make the linker find it if it's not there. Also, you said earlier:

It compiles but i get errors from sem_wait() when I run it.

So, which is it to be? Either it compiles or it doesn't.

I can't be any more specific than this.

Then nobody can help you.

I believe I'm missing a file or something is not linked properly.

Maybe you need to get this librt? But apparently not because it compiled and then you got "errors". Of course, nobody can tell you what to do to fix these "errors" because they don't know what these "errors" are. Any attempt to help you would be a stab in the dark, and expecting people to try and do your work for you is probably not going to get you any helpful responses.

Oh, and actually, I was being constructive. I was trying to cajole you into providing more information so that people could actually help you. You're apparently unable or unwilling to do so, and if that's the case then you shouldn't expect people to help you. Actually, you shouldn't expect people to help you at all, but anyway.

You'd do well to read this: http://www.catb.org/~esr/faqs/smart-questions.html