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-rw-r--r--Src/exec.c18
-rw-r--r--Src/init.c2
-rw-r--r--Src/signals.c2
3 files changed, 20 insertions, 2 deletions
diff --git a/Src/exec.c b/Src/exec.c
index 8edbf1dc9..daa7ba55c 100644
--- a/Src/exec.c
+++ b/Src/exec.c
@@ -64,7 +64,23 @@ int nohistsave;
/**/
mod_export int errflag;
-/* Status of return from a trap */
+/*
+ * Status of return from a trap.
+ * This is only active if we are inside a trap, else its value
+ * is irrelevant. It is initialised to -1 for a function trap and
+ * -2 for a non-function trap and if negative is decremented as
+ * we go deeper into functions and incremented as we come back up.
+ * The value is used to decide if an explicit "return" should cause
+ * a return from the caller of the trap; it does this by setting
+ * trapreturn to a status (i.e. a non-negative value).
+ *
+ * In summary, trapreturn is
+ * - zero unless we are in a trap
+ * - negative in a trap unless it has triggered. Code uses this
+ * to detect an active trap.
+ * - non-negative in a trap once it was triggered. It should remain
+ * non-negative until restored after execution of the trap.
+ */
/**/
int trapreturn;
diff --git a/Src/init.c b/Src/init.c
index cf6164321..fcbf9236c 100644
--- a/Src/init.c
+++ b/Src/init.c
@@ -191,7 +191,7 @@ loop(int toplevel, int justonce)
exit(lastval);
if (((!interact || sourcelevel) && errflag) || retflag)
break;
- if (trapreturn) {
+ if (trapreturn >= 0) {
lastval = trapreturn;
trapreturn = 0;
}
diff --git a/Src/signals.c b/Src/signals.c
index 022ee8fb5..61fff64a2 100644
--- a/Src/signals.c
+++ b/Src/signals.c
@@ -1085,6 +1085,7 @@ dotrapargs(int sig, int *sigtr, void *sigfn)
int trapret = 0;
int obreaks = breaks;
int oretflag = retflag;
+ int otrapreturn = trapreturn;
int isfunc;
int traperr;
@@ -1183,6 +1184,7 @@ dotrapargs(int sig, int *sigtr, void *sigfn)
trapret = trapreturn + 1;
}
traperr = errflag;
+ trapreturn = otrapreturn;
execrestore();
lexrestore();