✘~/workspace/gowork/src/pthread $ go build .
# pthread
ccode.c:12:15: warning: incompatible integer to pointer conversion passing
'pthread_t' (aka 'unsigned long') to parameter of type 'pthread_once_t *'
(aka 'int *') [-Wint-conversion]
/usr/include/pthread.h:495:42: note: passing argument to parameter
'__once_control' here
ccode.c:12:23: warning: null passed to a callee that requires a non-null
argument [-Wnonnull]
# pthread
ccode.c:11: error: undefined reference to 'pthread_join'
ccode.c:12: error: undefined reference to 'pthread_once'
/usr/lib/gcc/x86_64-linux-gnu/8/libgcc.a(generic-morestack-thread.o):function
__wrap_pthread_create: error: undefined reference to 'pthread_once'
--------------------------------
Make the pthread_join and pthread_once as comments and recompile the file
```bash
~/workspace/gowork/src/pthread $ ldd main
linux-vdso.so.1 (0x00007ffc58db4000)
libgo.so.13git => /home/jxzhang/.local/gollvm/lib64/libgo.so.13git
(0x00007fc599db0000)
libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fc599a12000)
libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007fc5997fa000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fc599409000)
/lib64/ld-linux-x86-64.so.2 (0x00007fc59b6cb000)
libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0
(0x00007fc5991ea000)
~/workspace/gowork/src/pthread $ nm
/home/jxzhang/.local/gollvm/lib64/libgo.so.13git | grep -E
"pthread_create|pthread_join|pthread_once"
w pthread_create
w pthread_once
0000000001089d70 t __wrap_pthread_create
~/workspace/gowork/src/pthread $ nm /lib/x86_64-linux-gnu/libpthread.so.0
| grep -E "pthread_create|pthread_join|pthread_once"
000000000000f9b0 t __GI___pthread_once
00000000000079b0 t __pthread_create_2_1
00000000000079b0 T pthread_create@@GLIBC_2.2.5
0000000000008b50 t __pthread_join
0000000000008b50 W pthread_join
000000000000f9b0 T __pthread_once
000000000000f9b0 W pthread_once
000000000000f850 t __pthread_once_slow
```
在2021年4月6日星期二 UTC+8 下午9:15:25<JX Zhang> 写道：
> I met some problem about pthread.
> I wrote a cgo demo which use some pthread_* function, but it compile failed
>
> ccode.c
> ```
> # include <stdio.h>
> # include "ccode.h"
> # include <pthread.h>
>
> int try_pthread(){
> pthread_t id;
> int ret, i = 0;
> ret = pthread_create(&id,NULL,(void *)thread,NULL);
> for(i=0;i<=5;i++)
> printf("This is main thread %d\n",i);
> pthread_join(id,NULL);
> pthread_once(id, NULL);
> return 0;
> }
>
> void thread()
> {
> int i=0;
> for(i=0;i<=5;i++)
> printf("this is thread %d\n",i);
> }
> ```
>
> main.go
> ```
> package main
>
> /*
> #cgo CFLAGS: -I./
> #cgo LDFLAGS: -L./
> #include "ccode.h"
> */
> import "C"
>
> func main() {
> _ = C.try_pthread()
> }
> ```
>
> the `pthread_create` can be searched, but the other two functions report
> this:
> ccode.c:11: error: undefined reference to 'pthread_join'
> ccode.c:12: error: undefined reference to 'pthread_once'
>
>
>
>
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