cgo doesn't like errno on Linux

[alberts]

What steps will reproduce the problem?

make

What is the expected output?

Should work.

What do you see instead?

gcc -m64 -g -fPIC -O2 -o _cgo1_.o _cgo_main.o err.cgo2.o _cgo_export.o
/usr/bin/ld: errno: TLS definition in /lib64/libc.so.6 section .tbss mismatches non-TLS
reference in _cgo_main.o
/lib64/libc.so.6: could not read symbols: Bad value
collect2: ld returned 1 exit status
make: *** [_cgo1_.o] Error 1

Which compiler are you using (5g, 6g, 8g, gccgo)?

6g

Which operating system are you using?

linux

Which revision are you using?  (hg identify)

5a1200fb329f tip

Attachments:

1. err.go (88 bytes)
2. err_test.go (78 bytes)
3. Makefile (87 bytes)

[alberts]

Comment 1:

Running Fedora 14 x86_64 with glibc-2.12.90-19.x86_64 and gcc-4.5.1-4.fc14.x86_64.

[rsc]

Comment 2:

I was able to reproduce using these files on Ubuntu Lucid.
I don't know what's wrong, but it doesn't matter since
that's not a safe use of errno anyway.  Every call into 
C might happen in a different OS thread, which means
that referring to errno directly is not guaranteed to
get the value you want.
Instead, use a two-element return from any C function to
get both the result and the error code atomically.
See http://golang.org/cmd/cgo/
I will change cgo to print an error when it sees C.errno.

Owner changed to r...@golang.org.

Status changed to WontFix.

[rsc]

Comment 3:

This issue was closed by revision 02327a7.

Status changed to Fixed.

[alberts]

Comment 4:

Cool, thanks.