diff options
Diffstat (limited to 'include/sane/sanei_thread.h')
| -rw-r--r-- | include/sane/sanei_thread.h | 38 |
1 files changed, 35 insertions, 3 deletions
diff --git a/include/sane/sanei_thread.h b/include/sane/sanei_thread.h index fa72481..6e68964 100644 --- a/include/sane/sanei_thread.h +++ b/include/sane/sanei_thread.h @@ -94,6 +94,38 @@ extern SANE_Bool sanei_thread_is_forked (void); */ extern SANE_Bool sanei_thread_is_valid (SANE_Pid pid); +/** Invalidate a SANE_Pid + * + * This "function" should be used to invalidate a SANE_Pid in a + * portable manner. + * + * @note + * When using pthreads, this only works for those implementations + * that opted to make pthread_t an arithmatic type. This is *not* + * required by the POSIX threads specification. The choice to do + * SANE_Pid invalidation by means of a macro rather than a proper + * function circumvents to need to pass a pointer. + * If we decide to implement SANE_Pid with a void* in the future, + * this can be changed into a proper function without the need to + * change existing code. + * + * For details on the pthread_t type, see in particular Issue 6 of + * http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/sys_types.h.html + */ +#define sanei_thread_invalidate(pid) ((pid) = (SANE_Pid)(-1)) + +/** Initialize a SANE_Pid + * + * This "function" should be used to initialize a SANE_Pid in a + * portable manner. + * + * @note + * This is at present just an alias of sanei_thread_invalidate. + * It seemed misleading to use the latter when intent clearly has + * initialization written all over it, hence the alias. + */ +#define sanei_thread_initialize sanei_thread_invalidate + /** Spawn a new task. * * This function should be used to start a new task. @@ -131,7 +163,7 @@ extern int sanei_thread_kill (SANE_Pid pid); * @param pid - the id of the task * @param sig - the signal to send * - * @return + * @return * - 0 - on success * - any other value - if an error occured while sending the signal */ @@ -139,7 +171,7 @@ extern int sanei_thread_sendsig (SANE_Pid pid, int sig); /** Wait for task termination. * - * This function waits until a task that has been terminated by + * This function waits until a task that has been terminated by * sanei_thread_kill(), sanei_thread_sendsys() or by any other means * is finished. * @@ -153,7 +185,7 @@ extern SANE_Pid sanei_thread_waitpid (SANE_Pid pid, int *status); /** Check the current status of the spawned task * - * + * * @param pid - the id of the task * * @return |