From a79fba0f20611338079e680493645c95ee677084 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Fri, 18 Mar 2022 18:33:05 -0700
Subject: Add awkloop example to man page.

---
 cppawk.1 | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

(limited to 'cppawk.1')

diff --git a/cppawk.1 b/cppawk.1
index 1f9589a..42902a6 100644
--- a/cppawk.1
+++ b/cppawk.1
@@ -104,6 +104,31 @@ Print the larger of field 1 or 2:
          #define max(a, b) ((a) > (b) ? (a) : (b))
          { print max($1, $2) /* C comment */ } #awk comment' 
 
+Implement awk-like processing loop within function, to process
+/proc/mounts:
+
+  #include "awkloop.h"
+
+  function main()
+  {
+    awkloop ("/proc/mounts") {
+      rule ($3 != "ext4") { nextrec }
+      rule ($2 == "/") { print $1 }
+    }
+  }
+
+  BEGIN {
+    main()
+  }
+
+Where
+.BI awkloop.h
+contains:
+
+  #define awkloop(file)  for (; getline < file || (close(file) && 0); )
+  #define nextrec        continue
+  #define rule(cond)     if (cond)
+
 .SH "SEE ALSO"
 awk(1), cpp(6)
 .SH BUGS
-- 
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