os: document that StartProcess puts files into blocking mode

Fixes #43894

Change-Id: I2add7b8a4f6ae69a5ef1c48703fde21a4b74307c
Reviewed-on: https://go-review.googlesource.com/c/go/+/321852
Trust: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

diff --git a/src/os/exec.go b/src/os/exec.go
index edb773a092b6d71d9a8c0ee521e7846659c444b4..bc75d4dd66c9103ccf27df5729baa074d4fa0cdd 100644 (file)
--- a/src/os/exec.go
+++ b/src/os/exec.go
@@ -54,6 +54,9 @@ type ProcAttr struct {
        // standard error. An implementation may support additional entries,
        // depending on the underlying operating system. A nil entry corresponds
        // to that file being closed when the process starts.
+       // On Unix systems, StartProcess will change these File values
+       // to blocking mode, which means that SetDeadline will stop working
+       // and calling Close will not interrupt a Read or Write.
        Files []*File
 
        // Operating system-specific process creation attributes.