diff options
Diffstat (limited to 'linuxthreads/Examples')
-rw-r--r-- | linuxthreads/Examples/ex18.c | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/linuxthreads/Examples/ex18.c b/linuxthreads/Examples/ex18.c new file mode 100644 index 0000000..642f6b4 --- /dev/null +++ b/linuxthreads/Examples/ex18.c @@ -0,0 +1,112 @@ +/* + * Beat up the pthread_key_create and pthread_key_delete + * functions. + */ + +#if 0 +#define CHATTY +#endif + +#include <stdio.h> +#include <errno.h> +#include <stdlib.h> +#include <pthread.h> + +const int beatup_iterations = 10000; +const int num_threads = 30; +const int max_keys = 500; + +struct key_list { + struct key_list *next; + pthread_key_t key; +}; + +struct key_list *key_list; +pthread_mutex_t key_lock = PTHREAD_MUTEX_INITIALIZER; + +/* + * Create a new key and put it at the tail of a linked list. + * If the linked list grows to a certain length, delete a key from the + * head of * the list. + */ + +static void +beat_up(void) +{ + struct key_list *new = malloc(sizeof *new); + struct key_list **iter, *old_key = 0; + int key_count = 0; + + if (new == 0) { + fprintf(stderr, "malloc failed\n"); + abort(); + } + + new->next = 0; + + if (pthread_key_create(&new->key, 0) != 0) { + fprintf(stderr, "pthread_key_create failed\n"); + abort(); + } + + if (pthread_getspecific(new->key) != 0) { + fprintf(stderr, "new pthread_key_t resolves to non-null value\n"); + abort(); + } + + pthread_setspecific(new->key, (void *) 1); + +#ifdef CHATTY + printf("created key\n"); +#endif + + pthread_mutex_lock(&key_lock); + + for (iter = &key_list; *iter != 0; iter = &(*iter)->next) + key_count++; + + *iter = new; + + if (key_count > max_keys) { + old_key = key_list; + key_list = key_list->next; + } + + pthread_mutex_unlock(&key_lock); + + if (old_key != 0) { +#ifdef CHATTY + printf("deleting key\n"); +#endif + pthread_key_delete(old_key->key); + } +} + +static void * +thread(void *arg) +{ + int i; + for (i = 0; i < beatup_iterations; i++) + beat_up(); + return 0; +} + +int +main(void) +{ + int i; + pthread_attr_t detached_thread; + + pthread_attr_init(&detached_thread); + pthread_attr_setdetachstate(&detached_thread, PTHREAD_CREATE_DETACHED); + + for (i = 0; i < num_threads; i++) { + pthread_t thread_id; + while (pthread_create(&thread_id, &detached_thread, thread, 0) == EAGAIN) { + /* let some threads die, so system can breathe. :) */ + sleep(1); + } + } + + pthread_exit(0); +} |