diff options
| -rw-r--r-- | lib/libc/gen/popen.3 | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/lib/libc/gen/popen.3 b/lib/libc/gen/popen.3 index c4278e5f3e38..b22a57ef132d 100644 --- a/lib/libc/gen/popen.3 +++ b/lib/libc/gen/popen.3 @@ -53,16 +53,19 @@ function a process by creating a bidirectional pipe forking, and invoking the shell. +Any streams opened by previous +.Fn popen +calls in the parent process are closed in the new child process. Historically, -.Nm popen +.Fn popen was implemented with a unidirectional pipe; hence many implementations of -.Nm popen +.Fn popen only allow the .Fa type argument to specify reading or writing, not both. Since -.Nm popen +.Nm is now implemented using a bidirectional pipe, the .Fa type argument may request a bidirectional data flow. |