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 | man pages section 3: Basic Library Functions Oracle Solaris 11 Information Library |
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| man pages section 3: Basic Library Functions Oracle Solaris 11 Information Library |
enable_extended_FILE_stdio(3C)
posix_spawnattr_getschedparam(3C)
posix_spawnattr_getschedpolicy(3C)
posix_spawnattr_getsigdefault(3C)
posix_spawnattr_getsigignore_np(3C)
posix_spawnattr_getsigmask(3C)
posix_spawnattr_setschedparam(3C)
posix_spawnattr_setschedpolicy(3C)
posix_spawnattr_setsigdefault(3C)
posix_spawnattr_setsigignore_np(3C)
posix_spawnattr_setsigmask(3C)
posix_spawn_file_actions_addclose(3C)
posix_spawn_file_actions_addclosefrom_np(3C)
posix_spawn_file_actions_adddup2(3C)
posix_spawn_file_actions_addopen(3C)
posix_spawn_file_actions_destroy(3C)
posix_spawn_file_actions_init(3C)
pthread_attr_getdetachstate(3C)
pthread_attr_getinheritsched(3C)
pthread_attr_getschedparam(3C)
pthread_attr_getschedpolicy(3C)
pthread_attr_setdetachstate(3C)
pthread_attr_setinheritsched(3C)
pthread_attr_setschedparam(3C)
pthread_attr_setschedpolicy(3C)
pthread_barrierattr_destroy(3C)
pthread_barrierattr_getpshared(3C)
pthread_barrierattr_setpshared(3C)
pthread_condattr_getpshared(3C)
pthread_condattr_setpshared(3C)
pthread_cond_reltimedwait_np(3C)
pthread_key_create_once_np(3C)
pthread_mutexattr_getprioceiling(3C)
pthread_mutexattr_getprotocol(3C)
pthread_mutexattr_getpshared(3C)
pthread_mutexattr_getrobust(3C)
pthread_mutexattr_setprioceiling(3C)
pthread_mutexattr_setprotocol(3C)
pthread_mutexattr_setpshared(3C)
pthread_mutexattr_setrobust(3C)
pthread_mutex_getprioceiling(3C)
pthread_mutex_reltimedlock_np(3C)
pthread_mutex_setprioceiling(3C)
pthread_rwlockattr_destroy(3C)
pthread_rwlockattr_getpshared(3C)
pthread_rwlockattr_setpshared(3C)
pthread_rwlock_reltimedrdlock_np(3C)
pthread_rwlock_reltimedwrlock_np(3C)
pthread_rwlock_timedrdlock(3C)
pthread_rwlock_timedwrlock(3C)
rctlblk_get_enforced_value(3C)
- generate an IPC key
#include <sys/ipc.h>key_tftok(const char *path,intid);
Theftok() function returns a key based onpath andid thatis usable in subsequent calls tomsgget(2),semget(2) andshmget(2). Thepathargument must be the pathname of an existing file that the processis able tostat(2).
Theftok() function will return the same key value for all pathsthat name the same file, when called with the sameid value,and will return different key values when called with differentid values.
If the file named bypath is removed while still referred toby a key, a call toftok() with the samepath andid returns an error. If the same file is recreated, then acall toftok() with the samepath andid is likely to returna different key.
Only the low order 8-bits ofid are significant. The behaviorofftok() is unspecified if these bits are 0.
Upon successful completion,ftok() returns a key. Otherwise,ftok() returns(key_t)-1and setserrno to indicate the error.
Theftok() function will fail if:
Search permission is denied for a component of the path prefix.
Too many symbolic links were encountered in resolvingpath.
The length of thepath argument exceeds{PATH_MAX} or a pathname component is longer than{NAME_MAX}.
A component ofpath does not name an existing file orpath is an empty string.
A component of the path prefix is not a directory.
Theftok() function may fail if:
Pathname resolution of a symbolic link produced an intermediate result whose length exceeds{PATH_MAX}.
For maximum portability,id should be a single-byte character.
Another way to compose keys is to include the project ID inthe most significant byte and to use the remaining portion as asequence number. There are many other ways to form keys, but itis necessary for each system to define standards for forming them. Ifsome standard is not adhered to, it will be possible for unrelated processesto unintentionally interfere with each other's operation. It is still possible tointerfere intentionally. Therefore, it is strongly suggested that the most significant byteof a key in some sense refer to a project so thatkeys do not conflict across a given system.
Since theftok() function returns a value based on theid givenand the file serial number of the file named bypath ina type that is no longer large enough to hold all fileserial numbers, it may return the same key for paths naming different fileson large filesystems.
Seeattributes(5) for descriptions of the following attributes:
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msgget(2),semget(2),shmget(2),stat(2),attributes(5),standards(5)
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