diff options
Diffstat (limited to 'lib/libc/sys/flock.2')
| -rw-r--r-- | lib/libc/sys/flock.2 | 40 |
1 files changed, 33 insertions, 7 deletions
diff --git a/lib/libc/sys/flock.2 b/lib/libc/sys/flock.2 index bb6abb7..466e347 100644 --- a/lib/libc/sys/flock.2 +++ b/lib/libc/sys/flock.2 @@ -39,10 +39,10 @@ .Nd "apply or remove an advisory lock on an open file" .Sh SYNOPSIS .Fd #include <sys/file.h> -.Fd #define LOCK_SH 1 /* shared lock */ -.Fd #define LOCK_EX 2 /* exclusive lock */ -.Fd #define LOCK_NB 4 /* don't block when locking */ -.Fd #define LOCK_UN 8 /* unlock */ +.Fd #define LOCK_SH 0x01 /* shared file lock */ +.Fd #define LOCK_EX 0x02 /* exclusive file lock */ +.Fd #define LOCK_NB 0x04 /* don't block when locking */ +.Fd #define LOCK_UN 0x08 /* unlock file */ .Ft int .Fn flock "int fd" "int operation" .Sh DESCRIPTION @@ -109,6 +109,28 @@ forks and the child explicitly unlocks the file, the parent will lose its lock. .Pp Processes blocked awaiting a lock may be awakened by signals. +.Sh IMPLEMENTATION NOTES +.Pp +In the non-threaded library +.Fn flock +is implemented as the +.Va flock +syscall. +.Pp +In the threaded library, the +.Va flock +syscall is assembled to +.Fn _thread_sys_flock +and +.Fn flock +is implemented as a function which locks +.Va fd +for read and write, then calls +.Fn _thread_sys_flock . +Before returning, +.Fn flock +unlocks +.Va fd . .Sh RETURN VALUES Zero is returned if the operation was successful; on an error a -1 is returned and an error code is left in @@ -131,15 +153,19 @@ is an invalid descriptor. The argument .Fa fd refers to an object other than a file. +.It Bq Er EOPNOTSUPP +The argument +.Fa fd +refers to an object that does not support file locking. .El .Sh SEE ALSO -.Xr open 2 , .Xr close 2 , .Xr dup 2 , .Xr execve 2 , -.Xr fork 2 +.Xr fork 2 , +.Xr open 2 .Sh HISTORY The -.Nm +.Fn flock function call appeared in .Bx 4.2 . |
