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
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@ -123,7 +123,19 @@ to be duplicated as
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dup2(fildes, newfildes)
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dup2(fildes, newfildes)
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.Ed
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.Ed
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.Pp
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.Pp
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had been called) when a new process is spawned using this file actions object.
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had been called) when a new process is spawned using this file actions object,
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except that the
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.Dv FD_CLOEXEC
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flag for
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.Fa newfildes
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is cleared even if
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.Fa fildes
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is equal to
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.Fa newfildes .
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The difference from
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.Fn dup2
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is useful for passing a particular file descriptor
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to a particular child process.
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.Pp
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.Pp
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The
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The
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.Fn posix_spawn_file_actions_addclose
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.Fn posix_spawn_file_actions_addclose
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@ -169,7 +181,16 @@ The
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and
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and
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.Fn posix_spawn_file_actions_addclose
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.Fn posix_spawn_file_actions_addclose
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functions conform to
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functions conform to
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.St -p1003.1-2001 .
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.St -p1003.1-2001 ,
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with the exception of the behavior of
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.Fn posix_spawn_file_actions_adddup2
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if
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.Fa fildes
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is equal to
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.Fa newfildes
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(clearing
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.Dv FD_CLOEXEC ) .
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A future update of the Standard is expected to require this behavior,
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.Sh HISTORY
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.Sh HISTORY
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The
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The
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.Fn posix_spawn_file_actions_addopen ,
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.Fn posix_spawn_file_actions_addopen ,
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