diff --git a/man2/ptrace.2 b/man2/ptrace.2
index a1b8b6fe8..997a73a8a 100644
--- a/man2/ptrace.2
+++ b/man2/ptrace.2
@@ -1045,7 +1045,8 @@ struct ptrace_syscall_info {
         } entry;
         struct {     /* op == PTRACE_SYSCALL_INFO_EXIT */
             __s64 rval;        /* System call return value */
-            __u8 is_error;     /* System call error flag */
+            __u8 is_error;     /* System call error flag;
+                                  Boolean: is rval != 0? */
         } exit;
         struct {     /* op == PTRACE_SYSCALL_INFO_SECCOMP */
             __u64 nr;          /* System call number */