Add comment to the top of most .c files explaining their purpose

p4raw-id: //depot/perl@23176

1 files changed, 9 insertions, 0 deletions

diff --git a/pp_sys.c b/pp_sys.c
index 4432a47676..b615d4ab5f 100644
--- a/pp_sys.c
+++ b/pp_sys.c
@@ -15,6 +15,15 @@
  * a rumour and a trouble as of great engines throbbing and labouring.
  */
 
+/* This file contains system pp ("push/pop") functions that
+ * execute the opcodes that make up a perl program. A typical pp function
+ * expects to find its arguments on the stack, and usually pushes its
+ * results onto the stack, hence the 'pp' terminology. Each OP structure
+ * contains a pointer to the relevant pp_foo() function.
+ *
+ * By 'system', we mean ops which interact with the OS, such as pp_open().
+ */
+
 #include "EXTERN.h"
 #define PERL_IN_PP_SYS_C
 #include "perl.h"