diff options
| -rw-r--r-- | tools/hi-q.c | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/tools/hi-q.c b/tools/hi-q.c index b2a4c7c..f2da44d 100644 --- a/tools/hi-q.c +++ b/tools/hi-q.c @@ -212,7 +212,9 @@ int main(int argc, char** argv, char const * const * env) { const int rEnd(0); // end of a pipe for reading const int wEnd(1); // end of a pipe for writing int sync[2]; + int resync[2]; if (pipe(sync) != 0) cerr << "sync pipe failed" << endl; + if (pipe(resync) != 0) cerr << "resync pipe failed" << endl; // At this point, there are some loop invariants; // (a) fd0 is open (standard input) and has the email msg, @@ -272,6 +274,7 @@ int main(int argc, char** argv, char const * const * env) { cerr << "*** kid " << ii << " setpgid OK" << endl; } +// everybody else has to wait for us to get this far if (ii == 0) { int junk(1); write(sync[wEnd], &junk, 1); @@ -283,7 +286,22 @@ int main(int argc, char** argv, char const * const * env) { << " pgid: " << getpgid(0) << " starts" << endl; #endif - usleep(50000); + close(resync[wEnd]); +// Now we wait for everybody else: + if (ii==0) { + int junk; + cerr << "about to read resync" << endl; + ssize_t rslt = read(resync[rEnd], &junk, 1); + if (rslt != 1) { + cerr << "bad sync ... 1 != " << rslt << endl; + } else { + cerr << "back from read resync, good: " << rslt << endl; + } + } + +//###### usleep(50000); + + // Now that we are through creating pipes, we don't // need to continue blocking fd1: close(1); @@ -324,18 +342,18 @@ int main(int argc, char** argv, char const * const * env) { } close(kid_end); +// Let kid #0 run a little ways: if (ii==0) { int junk; cerr << "about to read sync" << endl; ssize_t rslt = read(sync[rEnd], &junk, 1); - if (rslt != 1) { + if (rslt < 0) { cerr << "bad sync ... 1 != " << rslt << endl; } else { cerr << "back from read sync, good: " << rslt << endl; } } - // it is important to let kid#0 run a while; // otherwise it won't fully exist when the other kids start, // and depending race conditions, the setpgid could fail @@ -351,6 +369,8 @@ int main(int argc, char** argv, char const * const * env) { // here with the whole pipeline of kids launched + close(resync[wEnd]); + close(0); // the reading end of stdin was // delegated to the first child |