"Failed to link import function" for pthread functions in C++ #932
Description
I am trying to use threads in C++. Compiling the C++ code works without any errors. The command for compiling is shown below. The C++ code is a modification of the c pthread example in this repo. The same error occurs when compiling the c pthread example with the clang++ compiler without any modifications to the code. I am using wasi-sdk version 14.0.
When trying to run the code I am getting failed to link import function errors for the used pthread functions when trying to run code compiled with the C++ compiler. iwasm has no problem running the WebAssembly generated by the c compiler.
Failure with cpp
$ /opt/wasi-sdk/bin/clang++ -pthread -O3 \
-Wl,--shared-memory,--max-memory=196608 \
-Wl,--allow-undefined,--no-check-features \
-Wl,--export=__heap_base,--export=__data_end \
thread.cpp -o test.wasm
$ /home/vogel/code/wasm-micro-runtime/product-mini/platforms/linux/build/iwasm test.wasm
[02:27:23:182 - 7FB3EFFFA740]: warning: failed to link import function (env, _Z12pthread_exitPv)
[02:27:23:192 - 7FB3EFFFA740]: warning: failed to link import function (env, _Z14pthread_createPjPKvPFPvS2_ES2_)
[02:27:23:193 - 7FB3EFFFA740]: warning: failed to link import function (env, _Z12pthread_joinjPPv)
Exception: failed to call unlinked import function (env, _Z14pthread_createPjPKvPFPvS2_ES2_)
Code
#include <pthread.h>
#include
void *thread_routine(void *arg)
{
std::cout << "Enter thread\n";
pthread_exit(NULL);
return NULL;
}
int main(int argc, char** argv)
{
pthread_t tid;
if (0 != pthread_create(&tid, NULL, thread_routine, NULL)) {
std::cout << "Failed to create thread\n";
}
if (0 != pthread_join(tid, NULL)) {
std::cout << "Failed to join thread\n";
}
std::cout << "Exit\n";
return 0;
}
Working c
$ /opt/wasi-sdk/bin/clang -pthread -O3 \
-Wl,--shared-memory,--max-memory=196608 \
-Wl,--allow-undefined,--no-check-features \
-Wl,--export=__heap_base,--export=__data_end \
thread.c -o test.wasm
$ /home/vogel/code/wasm-micro-runtime/product-mini/platforms/linux/build/iwasm test.wasm
THREAD CREATED 7f92c9038700
Enter thread
Exit
Code
#include <stdio.h>
#include <pthread.h>
void *thread_routine(void *arg)
{
printf("Enter thread\n");
pthread_exit(NULL);
return NULL;
}
int main(int argc, char** argv)
{
pthread_t tid;
if (0 != pthread_create(&tid, NULL, thread_routine, NULL)) {
printf("Failed to create thread\n");
}
if (0 != pthread_join(tid, NULL)) {
printf("Failed to join thread %d.\n", tid);
}
printf("Exit\n");
return 0;
}
Same faulty behavior when compiling the c version with the clang++ compiler.