diff options
Diffstat (limited to 'bits/sem.h')
| -rw-r--r-- | bits/sem.h | 26 |
1 files changed, 17 insertions, 9 deletions
diff --git a/bits/sem.h b/bits/sem.h index 8b9f97c62a..cb6657a345 100644 --- a/bits/sem.h +++ b/bits/sem.h @@ -1,4 +1,5 @@ -/* Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc. +/* Copyright (C) 1995, 1996, 1997, 1998 + Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -44,11 +45,18 @@ struct semid_ds unsigned short int sem_nsems; /* number of semaphores in set */ }; -/* Union used for argument for `semctl'. */ -union semun -{ - int val; /* value for SETVAL */ - struct semid_ds *buf; /* buffer for IPC_STAT & IPC_SET */ - unsigned short int *array; /* array for GETALL & SETALL */ - struct seminfo *__buf; /* buffer for IPC_INFO */ - }; +/* The user should define a union like the following to use it for arguments + for `semctl'. + + union semun + { + int val; <= value for SETVAL + struct semid_ds *buf; <= buffer for IPC_STAT & IPC_SET + unsigned short int *array; <= array for GETALL & SETALL + struct seminfo *__buf; <= buffer for IPC_INFO + }; + + Previous versions of this file used to define this union but this is + incorrect. One can test the macro _SEM_SEMUN_UNDEFINED to see whether + one must define the union or not. */ +#define _SEM_SEMUN_UNDEFINED 1 |