fixes #5349

tests/stdlib/tio.nim

@@ -1,7 +1,39 @@
+discard """
+  output: '''9
+b = false
+123456789
+Second readLine raised an exception
+123456789
+'''
+"""
+# bug #5349
+import os
+
 # test the file-IO
 
-proc main() =
-  for line in lines("thello.nim"):
-    writeLine(stdout, line)
+const fn = "file9char.txt"
 
-main()
+writeFile(fn, "123456789")
+
+var f = open(fn)
+echo getFileSize(f)
+
+var line = newString(10)
+try:
+  let b = readLine(f, line)
+  echo "b = ", b
+except:
+  echo "First readLine raised an exception"
+
+echo line
+
+try:
+  line = readLine(f)
+  let b = readLine(f, line)
+  echo "b = ", b
+except:
+  echo "Second readLine raised an exception"
+
+echo line
+
+removeFile(fn)