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author | jilles <jilles@FreeBSD.org> | 2013-05-09 21:29:13 +0000 |
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committer | jilles <jilles@FreeBSD.org> | 2013-05-09 21:29:13 +0000 |
commit | dcf83719521d9ab2ddf5a05929e1fefe098bf175 (patch) | |
tree | 3fab2811f6c16b96724d366c7477ad71bdce3213 | |
parent | b0ca453ba0893a7c4b184f1cdd1bbd29a3d5f9e6 (diff) | |
download | FreeBSD-src-dcf83719521d9ab2ddf5a05929e1fefe098bf175.zip FreeBSD-src-dcf83719521d9ab2ddf5a05929e1fefe098bf175.tar.gz |
posix_spawn_file_actions_adddup2(3): Document difference with dup2().
The ability to clear a file descriptor's close-on-exec flag via
posix_spawn_file_actions_adddup2() is in fact proposed in Austin Group issue
#411.
MFC after: 1 week
-rw-r--r-- | lib/libc/gen/posix_spawn_file_actions_addopen.3 | 25 |
1 files changed, 23 insertions, 2 deletions
diff --git a/lib/libc/gen/posix_spawn_file_actions_addopen.3 b/lib/libc/gen/posix_spawn_file_actions_addopen.3 index e01b497..c466578 100644 --- a/lib/libc/gen/posix_spawn_file_actions_addopen.3 +++ b/lib/libc/gen/posix_spawn_file_actions_addopen.3 @@ -123,7 +123,19 @@ to be duplicated as dup2(fildes, newfildes) .Ed .Pp -had been called) when a new process is spawned using this file actions object. +had been called) when a new process is spawned using this file actions object, +except that the +.Dv FD_CLOEXEC +flag for +.Fa newfildes +is cleared even if +.Fa fildes +is equal to +.Fa newfildes . +The difference from +.Fn dup2 +is useful for passing a particular file descriptor +to a particular child process. .Pp The .Fn posix_spawn_file_actions_addclose @@ -169,7 +181,16 @@ The and .Fn posix_spawn_file_actions_addclose functions conform to -.St -p1003.1-2001 . +.St -p1003.1-2001 , +with the exception of the behavior of +.Fn posix_spawn_file_actions_adddup2 +if +.Fa fildes +is equal to +.Fa newfildes +(clearing +.Dv FD_CLOEXEC ) . +A future update of the Standard is expected to require this behavior, .Sh HISTORY The .Fn posix_spawn_file_actions_addopen , |