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digitalmars.D.learn - core.sys.posix.setjmp unavailable for OS X?

reply bpr <brogoff gmail.com> writes:
Is there a reason that it's unavailable on OS X when it works 
fine on Linux? The functions exist on OS X, and it's easy enough 
to compile C programs using setjmp there; but not D programs. I 
don't think I'm getting a betterC experience on the Mac.

I'd also ask why the there are no D docs for core.sys.posix but I 
read the responses to the last time the question was asked and 
now I'm D-pressed. :-(
Jan 15 2018
parent reply "H. S. Teoh" <hsteoh quickfur.ath.cx> writes:
On Mon, Jan 15, 2018 at 07:06:42PM +0000, bpr via Digitalmars-d-learn wrote:

 Is there a reason that it's unavailable on OS X when it works fine on
 Linux?  The functions exist on OS X, and it's easy enough to compile C
 programs using setjmp there; but not D programs. I don't think I'm
 getting a betterC experience on the Mac.


[...]

It's probably just a matter of adding the appropriate prototypes /
declarations to druntime. Provided that they actually work as
advertised, of course. There may be incompatibilities that I'm not aware
of that would preclude it from being added to druntime.

In any case, if druntime doesn't provide the right declarations, you
*could* just declare them yourself with an extern(C). E.g.:

	extern(C) int setjmp(jmp_buf env);
	extern(C) void longjmp(jmp_buf env, int val);
	...
	jmp_buf buf;
	int rc = setjmp(buf);
	if (rc == 0) {
		...
		longjmp(buf, rc);
	} else {
		// handle error
	}

You'll need to obtain your system's definition of jmp_buf, of course,
and translate it into D appropriately. You can find it in the usual
system include directories, like /usr/include or something along those
lines.  Most C structs can be copied verbatim into D and it would work.

(Note that you'll need to find the *exact* declaration used; especially
for structs, you may not be able to just use generic declarations given
by the Posix spec, because if your OS has additional fields for internal
use, you want to make sure those fields are declared properly, otherwise
the struct will have the wrong size and you may get problems at
runtime.)

Better yet, once you figure out how to do it, submit a PR against
druntime so that future users of your OS will benefit from it. ;-)


T

-- 
A program should be written to model the concepts of the task it performs
rather than the physical world or a process because this maximizes the
potential for it to be applied to tasks that are conceptually similar and, more
important, to tasks that have not yet been conceived. -- Michael B. Allen
Jan 15 2018
parent reply Jacob Carlborg <doob me.com> writes:
On 2018-01-15 20:37, H. S. Teoh wrote:


 It's probably just a matter of adding the appropriate prototypes /
 declarations to druntime. Provided that they actually work as
 advertised, of course.


They're used to implement Objective-C exceptions on macOS 32bit and iOS.

-- 
/Jacob Carlborg
Jan 15 2018
parent reply Jacob Carlborg <doob me.com> writes:
On 2018-01-16 08:29, Jacob Carlborg wrote:


 They're used to implement Objective-C exceptions on macOS 32bit and iOS.


Forgot the second part:

... so I assume that means it works.

-- 
/Jacob Carlborg
Jan 15 2018
parent "H. S. Teoh" <hsteoh quickfur.ath.cx> writes:
On Tue, Jan 16, 2018 at 08:29:57AM +0100, Jacob Carlborg via
Digitalmars-d-learn wrote:

 On 2018-01-16 08:29, Jacob Carlborg wrote:
 

 They're used to implement Objective-C exceptions on macOS 32bit and
 iOS.


 
 Forgot the second part:
 
 ... so I assume that means it works.


[...]

So we should add that to druntime, then.


T

-- 
MSDOS = MicroSoft's Denial Of Service
Jan 15 2018