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Diffstat (limited to 'linuxthreads/Examples/ex8.c')
-rw-r--r-- | linuxthreads/Examples/ex8.c | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/linuxthreads/Examples/ex8.c b/linuxthreads/Examples/ex8.c new file mode 100644 index 0000000000..bda81b9c61 --- /dev/null +++ b/linuxthreads/Examples/ex8.c @@ -0,0 +1,101 @@ +/* Tests for fork in multi-threaded environment. + Copyright (C) 2000 Free Software Foundation, Inc. + Contributed by Ulrich Drepper <drepper@cygnus.com>, 2000. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include <errno.h> +#include <error.h> +#include <stdlib.h> +#include <pthread.h> +#include <unistd.h> +#include <sys/wait.h> + +enum +{ + PREPARE_BIT = 1, + PARENT_BIT = 2, + CHILD_BIT = 4 +}; + +static int var; + +static void +prepare (void) +{ + var |= PREPARE_BIT; +} + +static void +parent (void) +{ + var |= PARENT_BIT; +} + +static void +child (void) +{ + var |= CHILD_BIT; +} + + +static void *thread (void *arg); + + +int +main (void) +{ + pthread_t th; + void *res; + + pthread_atfork (prepare, parent, child); + + if (pthread_create (&th, NULL, thread, NULL) != 0) + error (EXIT_FAILURE, 0, "cannot create thread"); + + pthread_join (th, &res); + + return (int) (long int) res; +} + + +static void * +thread (void *arg) +{ + int status; + pid_t pid; + + pid = fork (); + if (pid == 0) + { + /* We check whether the `prepare' and `child' function ran. */ + exit (var != (PREPARE_BIT | CHILD_BIT)); + } + else if (pid == (pid_t) -1) + error (EXIT_FAILURE, errno, "cannot fork"); + + if (waitpid (pid, &status, 0) != pid) + error (EXIT_FAILURE, errno, "wrong child"); + + if (WTERMSIG (status) != 0) + error (EXIT_FAILURE, 0, "Child terminated incorrectly"); + status = WEXITSTATUS (status); + + if (status == 0) + status = var != (PREPARE_BIT | PARENT_BIT); + + return (void *) (long int) status; +} |