Re: reentrant library functions

On Sep 18, 9:20 pm, David Schwartz <dav...@xxxxxxxxxxxxx> wrote:
On Sep 17, 1:29 pm, Mike <michael.h.william...@xxxxxxxxx> wrote:

On Sep 16, 10:01 pm, David Schwartz <dav...@xxxxxxxxxxxxx> wrote:
Hi, I am trying to create a library of some functions that allow
reentrancy, but I don't want to require compiling with the thread
library, "-lpthread", for programs that use my functions, but that
don't use threads. How do I do that?

Here you say you don't want to require *compiling* with the thread
library.

First, to correct one error in your post, '-lpthread' is a linker flag
and has no effect on compiling. You probably mean '-pthread', which on
many platforms (including Linux), selects compiling and linking for
pthreads support.
I do not quite understand.
My functions use semaphores to ensure that any threaded access
is exclusive (sem_wait() and sem_post()). I need the '-lpthread' flag,
or else I get linker errors.

If you were able to get linker errors, that means you had something to
link. That means that the compiling worked. So you *don't* need to
specify the '-lpthread' flag to compile. If you did, you would never
get linker errors because you'd have nothing to link.

You are using a platform that doesn't require any special compiler
flags to make thread-safe code. However, it's still good practice to
specify '-pthread' just in case. On Linux, this has no effect on
compilation and only affects linking.

I think I understand. I should have asked: For a program that uses
my functions, but not threads, is there a way it can be linked
without
having to state '-lpthread'.

(And, I do define _REENTRANT for compiling my functions.)

-Mike
.

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