External functions returning C_DOUBLE are called twice (bug?)
- Posted by ghaberek (admin) Dec 17, 2020
- 1194 views
Forked from Re: Phix+EuGTK
petelomax said...
irv said...
double hello(double x)Can anybody explain why I get two hello's?
LOL.
LOL indeed. It certainly looks like the function is being called twice. Very not good. One call is directly from call_c() and the second is from icall_x86_64(), which is called by call_c().
Here's a stack trace showing the function calls. I'll need to run this against a debug build to get a better stack output and see what's going on. Currently I'm just using the 4.1 beta build.
$ gdb eui GNU gdb (Ubuntu 8.1.1-0ubuntu1) 8.1.1 Reading symbols from eui...(no debugging symbols found)...done. (gdb) break hello Function "hello" not defined. Make breakpoint pending on future shared library load? (y or [n]) y Breakpoint 1 (hello) pending. (gdb) run libmytest.e Starting program: /usr/local/bin/eui libmytest.e [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". Breakpoint 1, 0x00007ffff701f62e in hello () from ./libmytest.so (gdb) bt #0 0x00007ffff701f62e in hello () from ./libmytest.so #1 0x000000000057b074 in call_c () #2 0x00000000005780e3 in do_exec () #3 0x0000000000578a63 in Execute () #4 0x000000000057d301 in start_backend () #5 0x000000000057def8 in machine () #6 0x00000000004274be in _68BackEnd () #7 0x00000000004fe69c in _2BackEnd () #8 0x00000000004fa93a in _74main () #9 0x000000000041e0bf in main () (gdb) cont Continuing. Hello! Your number was 123.456 Breakpoint 1, 0x00007ffff701f62e in hello () from ./libmytest.so (gdb) bt #0 0x00007ffff701f62e in hello () from ./libmytest.so #1 0x000000000057a590 in icall_x86_64 () #2 0x000000000057b09d in call_c () #3 0x00000000005780e3 in do_exec () #4 0x0000000000578a63 in Execute () #5 0x000000000057d301 in start_backend () #6 0x000000000057def8 in machine () #7 0x00000000004274be in _68BackEnd () #8 0x00000000004fe69c in _2BackEnd () #9 0x00000000004fa93a in _74main () #10 0x000000000041e0bf in main () (gdb) cont Continuing. Hello! Your number was 123.456 Got back: 246.912 warning: Temporarily disabling breakpoints for unloaded shared library "./libmytest.so" [Inferior 1 (process 2575) exited normally] (gdb) quit
-Greg
