From de1af0a3f26277abe8b4da2a0fe54436539a8ead Mon Sep 17 00:00:00 2001
From: Martin Dias <tinchodias@gmail.com>
Date: Thu, 18 Dec 2025 23:22:07 -0300
Subject: [PATCH] Use waitpid with WNOHANG option to know if the child process
 is running

---
 .../OSSubprocess/OSSUnixSubprocess.class.st   |  5 ++++-
 repository/OSSubprocess/OSSVMProcess.class.st | 20 ++++++++++++++++++-
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/repository/OSSubprocess/OSSUnixSubprocess.class.st b/repository/OSSubprocess/OSSUnixSubprocess.class.st
index 273e6bf..2a16b28 100644
--- a/repository/OSSubprocess/OSSUnixSubprocess.class.st
+++ b/repository/OSSubprocess/OSSUnixSubprocess.class.st
@@ -583,7 +583,10 @@ OSSUnixSubprocess >> isComplete [
 { #category : 'status' }
 OSSUnixSubprocess >> isRunning [
 	"Answers whether the process is still running or not (to our best knowledge)"
-	^ pid notNil and: [ self isComplete not ]
+
+	^ pid notNil and: [
+		self isComplete not and: [
+			OSSVMProcess vmProcess isChildRunning: pid ] ]
 ]
 
 { #category : 'status' }
diff --git a/repository/OSSubprocess/OSSVMProcess.class.st b/repository/OSSubprocess/OSSVMProcess.class.st
index 99fc6e7..4e8f44c 100644
--- a/repository/OSSubprocess/OSSVMProcess.class.st
+++ b/repository/OSSubprocess/OSSVMProcess.class.st
@@ -184,6 +184,12 @@ OSSVMProcess >> finalizePreviousSession [
 	self activeChildren do: [ :each | each stopWaiting ]
 ]
 
+{ #category : 'childs management' }
+OSSVMProcess >> includesChildPid: aPid [
+
+	^ childProcessList anySatisfy: [ :process | process pid = aPid ]
+]
+
 { #category : 'initialize - release' }
 OSSVMProcess >> initialize [
 	"Set my instance variables to reflect the state of the OS process in which 
@@ -259,6 +265,17 @@ OSSVMProcess >> initializeSignalHandlers [
 	
 ]
 
+{ #category : 'child watching' }
+OSSVMProcess >> isChildRunning: childPid [
+	"Use waitpid with WNOHANG option to know if the child process is running. 
+	See: https://man7.org/linux/man-pages/man3/wait.3p.html"
+
+	^ (self
+			primitiveWaitpid: childPid
+			statusPointer: nil
+			options: WNOHANG) = 0
+]
+
 { #category : 'cwd' }
 OSSVMProcess >> lockCwdWithValue: cwdNewValue encoding: encoding during: aBlock [
 	"This method is a complete hack in order to support a #cmd: option in OSSUnixSubprocess. 
@@ -306,7 +323,8 @@ OSSVMProcess >> pid [
 
 { #category : 'child watching' }
 OSSVMProcess >> primitiveWaitpid: aProcessId statusPointer: statusPointer options: optionBits [
-	
+	"See: https://linux.die.net/man/2/waitpid"
+
 	^ self ffiCall: #( int waitpid(int aProcessId, void* statusPointer, int optionBits) )
 ]