PR6836: $$vars extensions, $$return

1 files changed, 12 insertions, 4 deletions

diff --git a/stapprobes.5.in b/stapprobes.5.in
index c71f79d3..f1626166 100644
--- a/stapprobes.5.in
+++ b/stapprobes.5.in
@@ -334,6 +334,11 @@ $var\->field
 traversal to a structure's field.  The indirection operator
 may be repeated to follow more levels of pointers.
 .TP
+$return
+is available in return probes only for functions that are declared
+with a return value.
+.TP
+.TP
 $var[N]
 indexes into an array.  The index is given with a
 literal number.
@@ -344,12 +349,15 @@ sprintf("parm1=%x ... parmN=%x var1=%x ... varN=%x", parm1, ..., parmN,
 var1, ..., varN)
 .TP
 $$locals
-expands to a character string that is equivalent to
-sprintf("var1=%x ... varN=%x", var1, ..., varN)
+expands to a subset of $$vars for only local variables.
 .TP
 $$parms
-expands to a character string that is equivalent to
-sprintf("parm1=%x ... parmN=%x", parm1, ..., parmN)
+expands to a subset of $$vars for only function parameters.
+.TP
+$$return
+is available in return probes only.  It expands to a string that
+is equivalent to sprintf("$return=%x", $return)
+if the probed function has a return value, or else an empty string.
 .PP
 For ".return" probes, context variables other than the "$return"
 value itself are only available for the function call parameters.