Bug #15072: thread.c:4356:5: error: implicit declaration of function ‘ubf_list_atfork’

• Status: Closed
• Assignee: normalperson (Eric Wong)
• Target version: -
• ruby -v: ruby 2.6.0dev (2018-08-01 trunk 64156) [x86_64-cygwin]
• Backport: 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN
• Tags: cygwin, build

[duerst (Martin Dürst)]

When compiling on cygwin, I get the following error:

compiling thread.c
thread.c: In function ‘rb_thread_atfork_internal’:
thread.c:4356:5: error: implicit declaration of function ‘ubf_list_atfork’ [-Werror=implicit-function-declaration]
     ubf_list_atfork();
     ^~~~~~~~~~~~~~~

The ubf_list_atfork function was introduced by issue #15013 in r64485.

The problem is that the function is defined as static in thread_pthread.c, but is used in thread.c. Not being an expert on threads, I thought that maybe ubf_list_atfork is a function that's available on some OSes, but that can't be the case. I only got empty results when searching for it.

There's also a macro for ubf_list_atfork in thread_win32.c, but that doesn't seem to be related here.

[below it says my Ruby version is trunk 64156, but I'm compiling on HEAD.]

[normalperson (Eric Wong)]

[e-mail] wrote:

https://bugs.ruby-lang.org/issues/15072

I think copying the macro for win32 for the !USE_UBF_LIST
case should work(*). Can you test and commit if it works?
(too tired and might not be back online soon)

diff --git a/thread_pthread.c b/thread_pthread.c
index 0159b65291..2fc8f1d681 100644
--- a/thread_pthread.c
+++ b/thread_pthread.c
@@ -1379,7 +1379,8 @@ ubf_wakeup_all_threads(void)
 #define ubf_select 0
static void ubf_wakeup_all_threads(void) { return; }
static int ubf_threads_empty(void) { return 1; }
+#define ubf_list_atfork() do {} while (0)
 #endif /* USE_UBF_LIST */

 #define TT_DEBUG 0
 #define WRITE_CONST(fd, str) (void)(write((fd),(str),sizeof(str)-1)<0)

Something similar for ubf_timer_disarm() might be needed, too.

(*) Because ubf_list stuff is disabled on Cygwin (Not sure why,
it's always been that way):

#if defined(SIGVTALRM) && !defined(CYGWIN)

define USE_UBF_LIST 1

#endif

[duerst (Martin Dürst)]

• Status changed from Open to Closed

That fix worked, thanks! Committed with r64635, okay on travis, not sure about other CIs.

[duerst (Martin Dürst)]

• Related to Bug #15130: Nested Timeouts hang on cygwin added

[duerst (Martin Dürst)]

• Status changed from Closed to Open

duerst (Martin Dürst) wrote:

That fix worked, thanks! Committed with r64635, okay on travis, not sure about other CIs.

Sorry for reopening. It seemed to work, but it left #15130. So I'm reopening this.

The issue here started with the commit at r64485.

Any help appreciated!

[normalperson (Eric Wong)]

• Status changed from Open to Closed

Fixed in #15130