Re: Determining OS at Runtime
Re: Determining OS at Runtime
- Subject: Re: Determining OS at Runtime
- From: Steve Christensen <email@hidden>
- Date: Thu, 02 Jul 2009 16:29:14 -0700
On Jul 1, 2009, at 5:22 PM, Sherm Pendley wrote:
On Wed, Jul 1, 2009 at 7:24 PM,
iseecolors<email@hidden> wrote:
I need to support 10.4 in my application, but it uses some Carbon
APIs that
are deprecated in 10.5 and I am using some new 10.5 APIs that
require the
10.5 SDK.
I am sure I have seen this before, but I have been unable to find
it in the
Archive. How do I determine at runtime which OS version I am
running on?
Just check for the presence of the function you want to call. In
Xcode, set your deployment target to 10.4, so that Leopard-only
symbols will be weak-linked. Then just check the symbol for NULL
before calling it:
if (SomeLeopardFunction != NULL) {
SomeLeopardFunction();
} else {
TigerFunction();
}
If you want to make sure that you don't include any "old" code in
your executable when you decide to make 10.5 (for example) your base
OS version, you could arrange your code like this:
#if MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_5
if (SomeLeopardFunction == NULL)
TigerFunction();
else
#endif
SomeLeopardFunction();
...then the compiler will take care of sorting out the details for
you. If you use that sequence in several places, it might even be
worthwhile to create an inline wrapper function in a header file so
the OS-specific details are kept in one place:
inline void SomeFunction()
{
#if MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_5
if (SomeLeopardFunction == NULL)
TigerFunction();
else
#endif
SomeLeopardFunction();
}
steve
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