Determining if the pthread_setname_np exist failed with the following output: Change Dir: /home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp Run Build Command(s):/usr/bin/make cmTC_7c40b/fast && make[1]: Entering directory `/home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp' /usr/bin/make -f CMakeFiles/cmTC_7c40b.dir/build.make CMakeFiles/cmTC_7c40b.dir/build make[2]: Entering directory `/home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp' Building C object CMakeFiles/cmTC_7c40b.dir/CheckSymbolExists.c.o /usr/bin/gcc -O2 -I/home/buildroot/autobuild/run/instance-0/output-1/host/include -fPIE -o CMakeFiles/cmTC_7c40b.dir/CheckSymbolExists.c.o -c /home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp/CheckSymbolExists.c /home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp/CheckSymbolExists.c: In function 'main': /home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp/CheckSymbolExists.c:8:19: error: 'pthread_setname_np' undeclared (first use in this function) return ((int*)(&pthread_setname_np))[argc]; ^ /home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp/CheckSymbolExists.c:8:19: note: each undeclared identifier is reported only once for each function it appears in make[2]: *** [CMakeFiles/cmTC_7c40b.dir/CheckSymbolExists.c.o] Error 1 make[2]: Leaving directory `/home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp' make[1]: *** [cmTC_7c40b/fast] Error 2 make[1]: Leaving directory `/home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp' File /home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp/CheckSymbolExists.c: /* */ #include int main(int argc, char** argv) { (void)argv; #ifndef pthread_setname_np return ((int*)(&pthread_setname_np))[argc]; #else (void)argc; return 0; #endif } Performing C SOURCE FILE Test CMAKE_HAVE_LIBC_PTHREAD failed with the following output: Change Dir: /home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp Run Build Command(s):/usr/bin/make cmTC_2256f/fast && make[1]: Entering directory `/home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp' /usr/bin/make -f CMakeFiles/cmTC_2256f.dir/build.make CMakeFiles/cmTC_2256f.dir/build make[2]: Entering directory `/home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp' Building C object CMakeFiles/cmTC_2256f.dir/src.c.o /usr/bin/gcc -O2 -I/home/buildroot/autobuild/run/instance-0/output-1/host/include -DCMAKE_HAVE_LIBC_PTHREAD -fPIE -o CMakeFiles/cmTC_2256f.dir/src.c.o -c /home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp/src.c Linking C executable cmTC_2256f /home/buildroot/autobuild/run/instance-0/output-1/host/bin/cmake -E cmake_link_script CMakeFiles/cmTC_2256f.dir/link.txt --verbose=1 /usr/bin/gcc -O2 -I/home/buildroot/autobuild/run/instance-0/output-1/host/include -DCMAKE_HAVE_LIBC_PTHREAD -L/home/buildroot/autobuild/run/instance-0/output-1/host/lib -Wl,-rpath,/home/buildroot/autobuild/run/instance-0/output-1/host/lib CMakeFiles/cmTC_2256f.dir/src.c.o -o cmTC_2256f CMakeFiles/cmTC_2256f.dir/src.c.o: In function `main': src.c:(.text.startup+0x15): undefined reference to `pthread_create' src.c:(.text.startup+0x1f): undefined reference to `pthread_detach' src.c:(.text.startup+0x2b): undefined reference to `pthread_join' src.c:(.text.startup+0x36): undefined reference to `pthread_atfork' collect2: error: ld returned 1 exit status make[2]: *** [cmTC_2256f] Error 1 make[2]: Leaving directory `/home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp' make[1]: *** [cmTC_2256f/fast] Error 2 make[1]: Leaving directory `/home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp' Source file was: #include void* test_func(void* data) { return data; } int main(void) { pthread_t thread; pthread_create(&thread, NULL, test_func, NULL); pthread_detach(thread); pthread_join(thread, NULL); pthread_atfork(NULL, NULL, NULL); pthread_exit(NULL); return 0; } Determining if the function pthread_create exists in the pthreads failed with the following output: Change Dir: /home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp Run Build Command(s):/usr/bin/make cmTC_2bd47/fast && make[1]: Entering directory `/home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp' /usr/bin/make -f CMakeFiles/cmTC_2bd47.dir/build.make CMakeFiles/cmTC_2bd47.dir/build make[2]: Entering directory `/home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp' Building C object CMakeFiles/cmTC_2bd47.dir/CheckFunctionExists.c.o /usr/bin/gcc -O2 -I/home/buildroot/autobuild/run/instance-0/output-1/host/include -DCHECK_FUNCTION_EXISTS=pthread_create -fPIE -o CMakeFiles/cmTC_2bd47.dir/CheckFunctionExists.c.o -c /home/buildroot/autobuild/run/instance-0/output-1/host/share/cmake-3.15/Modules/CheckFunctionExists.c Linking C executable cmTC_2bd47 /home/buildroot/autobuild/run/instance-0/output-1/host/bin/cmake -E cmake_link_script CMakeFiles/cmTC_2bd47.dir/link.txt --verbose=1 /usr/bin/gcc -O2 -I/home/buildroot/autobuild/run/instance-0/output-1/host/include -DCHECK_FUNCTION_EXISTS=pthread_create -L/home/buildroot/autobuild/run/instance-0/output-1/host/lib -Wl,-rpath,/home/buildroot/autobuild/run/instance-0/output-1/host/lib CMakeFiles/cmTC_2bd47.dir/CheckFunctionExists.c.o -o cmTC_2bd47 -lpthreads /usr/bin/ld: cannot find -lpthreads collect2: error: ld returned 1 exit status make[2]: *** [cmTC_2bd47] Error 1 make[2]: Leaving directory `/home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp' make[1]: *** [cmTC_2bd47/fast] Error 2 make[1]: Leaving directory `/home/buildroot/autobuild/run/instance-0/output-1/build/host-grpc-1.25.0/CMakeFiles/CMakeTmp'