Converting launch_activate_socket() from C to Pascal - issues

[trev]

After having successfully converted  the SampleD C daemon code into working, non-deprecated C code (ie replacing the deprecated ASL logging with OSLog; replacing the myriad deprecated launch_ functions with launch_activate_socket) my quest to convert it into Pascal has hit a pot hole, er, wall.

My working, converted, C code:

Code: C  [Select][+][-]

1. #include <launch.h>
2. [...]
3.  int *listening_fd_array;
4.  size_t listening_fds_count;
5.  int err;
6. [...]
7. err = launch_activate_socket("MySocket", &listening_fd_array, &listening_fds_count);
8. if (err != 0) {
9.    os_log_error(OS_LOG_DEFAULT, "launch_activate_socket() failed error %d (%s)", err, strerror(err));
10. }
11.  
12. if (NULL == listening_fd_array) {
13.     os_log_error(OS_LOG_DEFAULT, "No known sockets found to answer requests on!");
14.     retval = EXIT_FAILURE;
15.     goto done;
16. }

My failed Pascal attempt:

Code: Pascal  [Select][+][-]

1. function launch_activate_socket(const name: string; var fds: PInteger; cnt: size_t): integer; external name '_launch_activate_socket';
2.  
3. [...]
4. var
5.   err : integer;
6.   listening_fd_array: PInteger;
7.   listening_fds_count: size_t;
8.  
9. [...]
10. err := launch_activate_socket('MySocket', listening_fd_array, listening_fds_count);
11. if(err <> 0) then
12.   begin
13.     if(err = ENOENT) then
14.       writeln('Error: Socket not found in plist file (', err, ')')
15.     else if(err = ESRCH) then
16.       writeln('Error: Calling process is not managed by launchd (', err, ')')
17.     else if(err = EALREADY) then
18.       writeln('Error: Socket already activated (', err, ')')
19.     else
20.       writeln('Error: ', err);
21.   end;
22.  
23. if(Nil = listening_fds_count) then
24.   begin
25.     writeln('No known sockets found to answer requests on!');
26.     goto Done;
27.   end;

Where did I go wrong? It compiles successfully, but errors out with ESRCH and "No known sockets...".

[PascalDragon]

I have really strong doubts that launch_activate_socket as a C function takes a Pascal string instead of a PChar. Also shouldn't your cnt parameter be a var (or out) as well?
(Also I doubt that Nil = listening_fds_count does indeed compile)

[trev]

Dang (cut 'n paste errors from another version):
- Nil should have been 0
- string should have been pchar

Thanks - I'd missed the missing var. No more spurious errors

[PascalDragon]

Thanks - I'd missed the missing var. No more spurious errors

You're welcome.