ref: a351bcdccdf5a4273bc8dc3360a48fbb8b8aa9ea
dir: /src/lock.c/
#include <u.h> #include <libc.h> int cnt; Lock cntlck; void main(int, char*[]) { int i; if (rfork(RFPROC|RFMEM|RFNOWAIT) < 0) sysfatal("fork: %r"); for (i = 0; i < 2; i++){ lock(&cntlck); cnt++; unlock(&cntlck); } print("cnt is %d\n", cnt); exits(nil); }