diff options
Diffstat (limited to 'butl/fdstream')
| -rw-r--r-- | butl/fdstream | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/butl/fdstream b/butl/fdstream index 8d6385f..6697dd9 100644 --- a/butl/fdstream +++ b/butl/fdstream @@ -487,7 +487,9 @@ namespace butl // Windows permissions other than ru and wu are unlikelly to have effect. // // Also note that on POSIX the FD_CLOEXEC flag is set for the file descriptor - // to prevent its leakage into child processes. + // to prevent its leakage into child processes. On Windows, for the same + // purpose, the _O_NOINHERIT flag is set. Note that the process class, that + // passes such a descriptor to the child, makes it inheritable for a while. // LIBBUTL_EXPORT auto_fd fdopen (const char*, @@ -516,9 +518,16 @@ namespace butl // Note that on POSIX the FD_CLOEXEC flag is set for the new descriptor if it // is present for the source one. That's in contrast to POSIX dup() that // doesn't copy file descriptor flags. Also note that duplicating descriptor - // and setting the flag is not an atomic operation. + // and setting the flag is not an atomic operation generally, but it is in + // regards to child process spawning (to prevent file descriptor leakage into + // a child process). // - // @@ Should we copy HANDLE_FLAG_INHERIT flag on Windows as well? + // Note that on Windows the _O_NOINHERIT flag is set for the new descriptor + // if it is present for the source one. That's in contrast to Windows _dup() + // that doesn't copy the flag. Also note that duplicating descriptor and + // setting the flag is not an atomic operation generally, but it is in + // regards to child process spawning (to prevent file descriptor leakage into + // a child process). // LIBBUTL_EXPORT auto_fd fddup (int fd); @@ -608,8 +617,10 @@ namespace butl // automatically closed by the child process to prevent undesired behaviors // (such as child deadlock on read from a pipe due to the write-end leakage // into the child process). Opening pipe and setting the flag is not an - // atomic operation. Also note that you don't need to reset the flag for a - // pipe end being passed to the process class ctor. + // atomic operation generally, but it is in regards to child process spawning + // (to prevent file descriptor leakage into child processes spawned from + // other threads). Also note that you don't need to reset the flag for a pipe + // end being passed to the process class ctor. // LIBBUTL_EXPORT fdpipe fdopen_pipe (fdopen_mode = fdopen_mode::none); |