Enable prefetching backtace

Signed-off-by: Mattias Andrée <maandree@kth.se>

4 files changed, 26 insertions, 4 deletions

diff --git a/internal.c b/internal.c
index 034a2db..bad884e 100644
--- a/internal.c
+++ b/internal.c
@@ -4,3 +4,4 @@
 
 _Thread_local struct liberror_error liberror_error_;
 _Thread_local int liberror_have_error_;
+_Thread_local struct liberror_backtrace *liberror_saved_backtrace;
diff --git a/internal.h b/internal.h
index eb122ed..db33be9 100644
--- a/internal.h
+++ b/internal.h
@@ -29,6 +29,4 @@ struct liberror_backtrace {
 
 HIDDEN extern _Thread_local struct liberror_error liberror_error_;
 HIDDEN extern _Thread_local int liberror_have_error_;
-
-
-int liberror_save_backtrace(struct liberror_error *);
+extern _Thread_local struct liberror_backtrace *liberror_saved_backtrace;
diff --git a/liberror.h b/liberror.h
index 508dbac..7b5176a 100644
--- a/liberror.h
+++ b/liberror.h
@@ -180,6 +180,24 @@ void liberror_reset_error(void);
 void liberror_print_backtrace(struct liberror_error *, FILE *, const char *);
 
 /**
+ * Get backtrace and save backtrace
+ * 
+ * This function will never change `errno`
+ * 
+ * Note: this library does not actually save
+ * a backtrace, `-lerror-backtrace` is needed
+ * for that functionallity (it will replace
+ * some things in this library, so no other
+ * action is required)
+ * 
+ * @param   error  The error the backtrace shall be stored in,
+ *                 if `NULL`, the backtrafe is saved for the
+ *                 next error in the thread
+ * @return         0 on success, -1 on failure
+ */
+int liberror_save_backtrace(struct liberror_error *);
+
+/**
  * Set the current error for the thread
  * 
  * If the thread already has an error saved,
diff --git a/set_error.c b/set_error.c
index 38617c7..a44aac6 100644
--- a/set_error.c
+++ b/set_error.c
@@ -33,7 +33,12 @@ liberror_set_error(const char description[256], const char source[64], const cha
 	stpcpy(error->source, source);
 	stpcpy(error->code_group, code_group);
 	error->code = code;
-	liberror_save_backtrace(error);
+	if (liberror_saved_backtrace) {
+		error->backtrace = liberror_saved_backtrace;
+		liberror_saved_backtrace = NULL;
+	} else {
+		liberror_save_backtrace(error);
+	}
 	error->cause = cause;
 	error->failed_to_allocate_cause = have_cause && !cause;
 }