id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
6831	__sync_lock_test_and_set_4 and illegal instruction	Pascal Kesseli <pascal.kesseli@…>	chris_kohlhoff	"In the attachment, I’ve prepared a simple test program verifying a trivial asynchronous read operation using asio sockets. The program compiles and runs fine up to boost version 1.42. In version 1.43, compiling the program fails with a linker error:

{{{
/tmp/ccQi0dGl.o: In function `boost::asio::detail::gcc_fenced_block::gcc_fenced_block()':
main.cpp:(.text._ZN5boost4asio6detail16gcc_fenced_blockC1Ev[boost::asio::detail::gcc_fenced_block::gcc_fenced_block()]+0x4c): undefined reference to `__sync_lock_test_and_set_4'
}}}

Since version 1.44 up to version 1.49, the linker error is gone and the program compiles fine. However, the program aborts at runtime upon executing “io.run()”, issuing an “Illegal instruction” error message. My assumption is that whatever “_sync_lock_test_and_set_4” was replaced by in version 1.44 represents an illegal operation on my target system.

The target system is a MOXA UC-8410 embedded ARM computer:

{{{
Linux Moxa 2.6.23.1 #1044 Fri May 6 10:25:20 CST 2011 armv5teb GNU/Linux
arm-linux-g++ (GCC) 4.2.1
}}}
"	Bugs	new	To Be Determined	asio	Boost 1.43.0	Showstopper		async_read __sync_lock_test_and_set_4 illegal_instruction