From: Mark Wooding <mdw@distorted.org.uk>
Date: Fri, 4 Oct 2019 15:22:15 +0000 (+0100)
Subject: mdwsetup.py (progoutput): Only read one byte to decide whether there is more.
X-Git-Url: https://git.distorted.org.uk/~mdw/runlisp/commitdiff_plain/514f1de64a582d3a183b853990484a2ac72f86a8

mdwsetup.py (progoutput): Only read one byte to decide whether there is more.

There's no point in slurping the entire output now that we're closing
the pipe /before/ trying to waitpid(2): the child will hit `SIGPIPE' (or
`EPIPE') rather than blocking on output.
---

diff --git a/mdwsetup.py b/mdwsetup.py
index 57832a2..0210714 100644
--- a/mdwsetup.py
+++ b/mdwsetup.py
@@ -76,7 +76,7 @@ def progoutput(command):
   kid = SUB.Popen(command, stdout = SUB.PIPE)
   try:
     out = kid.stdout.readline()
-    junk = kid.stdout.read()
+    junk = kid.stdout.read(1)
   finally:
     kid.stdout.close()
   if junk != '': raise ValueError \