Re: Add SHELL_EXIT_CODE to psql

Hi!

The patch is implementing what is declared to do. Shell return code is now
accessible is psql var.
Overall code is in a good condition. Applies with no errors on master.
Unfortunately, regression tests are failing on the macOS due to the
different shell output.

@@ -1308,13 +1308,13 @@
deallocate q;
-- test SHELL_EXIT_CODE
\! nosuchcommand
-sh: line 1: nosuchcommand: command not found
+sh: nosuchcommand: command not found
\echo :SHELL_EXIT_CODE
127
\set nosuchvar `nosuchcommand`
-sh: line 1: nosuchcommand: command not found
+sh: nosuchcommand: command not found
\! nosuchcommand
-sh: line 1: nosuchcommand: command not found
+sh: nosuchcommand: command not found
\echo :SHELL_EXIT_CODE
127

Since we do not want to test shell output in these cases, but only return
code,
what about using this kind of commands?
postgres=# \! true > /dev/null 2>&1
postgres=# \echo :SHELL_EXIT_CODE
0
postgres=# \! false > /dev/null 2>&1
postgres=# \echo :SHELL_EXIT_CODE
1
postgres=# \! nosuchcommand > /dev/null 2>&1
postgres=# \echo :SHELL_EXIT_CODE
127

It is better to use spaces around "=".
+ if (WIFEXITED(exit_code))
+ exit_code=WEXITSTATUS(exit_code);
+ else if(WIFSIGNALED(exit_code))
+ exit_code=WTERMSIG(exit_code);
+ else if(WIFSTOPPED(exit_code))
+ exit_code=WSTOPSIG(exit_code);

--
Best regards,
Maxim Orlov.