Bug 361253

Summary:	[s390x] ex_clone.c:42: undefined reference to `pthread_create'
Product:	[Developer tools] valgrind	Reporter:	dann frazier <dannf>
Component:	general	Assignee:	Julian Seward <jseward>
Status:	RESOLVED FIXED
Severity:	normal	CC:	arnez, borntraeger, dannf
Priority:	NOR
Version First Reported In:	3.11 SVN
Target Milestone:	---
Platform:	Compiled Sources
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	Move -lpthread to end of linker command line

Description dann frazier 2016-03-31 21:48:13 UTC

'make regtest' on trunk currently fails on Ubuntu 16.04/s390x.

gcc -Winline -Wall -Wshadow -Wno-long-long -g -fno-stack-protector   -m64   -lpthread  -o ex_clone ex_clone.o  
ex_clone.o: In function `main':
/home/ubuntu/valgrind/none/tests/s390x/ex_clone.c:42: undefined reference to `pthread_create'
/home/ubuntu/valgrind/none/tests/s390x/ex_clone.c:57: undefined reference to `pthread_join'
collect2: error: ld returned 1 exit status
Makefile:1324: recipe for target 'ex_clone' failed



Reproducible: Always

Steps to Reproduce:
1. Install Ubuntu 16.04 on an s390x system
2. svn clone svn://svn.valgrind.org/valgrind/trunk valgrind
3. cd valgrind; ./autogen.sh; ./configure; make regtest


Actual Results:  
gcc -Winline -Wall -Wshadow -Wno-long-long -g -fno-stack-protector   -m64   -lpthread  -o ex_clone ex_clone.o  
ex_clone.o: In function `main':
/home/ubuntu/valgrind/none/tests/s390x/ex_clone.c:42: undefined reference to `pthread_create'
/home/ubuntu/valgrind/none/tests/s390x/ex_clone.c:57: undefined reference to `pthread_join'
collect2: error: ld returned 1 exit status
Makefile:1324: recipe for target 'ex_clone' failed

Expected Results:  
Successful build.

Comment 1 dann frazier 2016-03-31 21:51:00 UTC

Created attachment 98183 [details]
Move -lpthread to end of linker command line

Comment 2 Christian Borntraeger 2016-09-20 12:21:59 UTC

I can certaiinly apply this patch, but I am puzzled. 

why does

gcc  -Winline -Wall -Wshadow -Wno-long-long -g -fno-stack-protector   -m64   -o ex_clone none/tests/s390x/ex_clone.o -lpthread 

work
and
gcc  -Winline -Wall -Wshadow -Wno-long-long -g -fno-stack-protector   -m64   -lpthread -o ex_clone none/tests/s390x/ex_clone.o
does not?

Comment 3 Christian Borntraeger 2016-09-20 12:32:19 UTC

OK, seems that library ordering does indeed matter.
applied as r15970