Completion of error handling

[elfring]

Would you like to add more error handling for return values from functions like the following?

• fdopen ⇒ dns_open
• printf ⇒ xml_close

[elfring]

How do you think about to integrate the following change possibilities besides further source code adjustments? :thinking:

diff --git a/ui/report.c b/ui/report.c
index 9301480..15f6767 100644
--- a/ui/report.c
+++ b/ui/report.c
@@ -45,6 +45,12 @@
 #define MAXLOADBAL 5
 #define MAX_FORMAT_STR 320
 
+#define LINE_BREAK_OUTPUT \
+        if (putchar('\n') != '\n') { \
+            perror("Output failed for a line break"); \
+            exit(EXIT_FAILURE); \
+        }
+
 
 void report_open(
     void)
@@ -385,7 +391,8 @@ void json_close(struct mtr_ctl *ctl)
     if (ret == -1)
         goto on_error;
 
-    printf("\n"); // bash prompt should be on new line
+    // bash prompt should be on new line
+    LINE_BREAK_OUTPUT
     json_decref(jreport);
     return;
 on_error:
@@ -500,7 +507,8 @@ void csv_close(
                     continue;
                 printf("%s,", data_fields[j].title);
             }
-            printf("\n");
+
+            LINE_BREAK_OUTPUT
         }
 #ifdef HAVE_IPINFO
         if (!ctl->ipinfo_no) {
@@ -527,7 +535,9 @@ void csv_close(
                 printf(",%d", data_fields[j].net_xxx(at));
             }
         }
-        printf("\n");
+
+        LINE_BREAK_OUTPUT
+
         if (ctl->reportwide == 0)
             continue;
         
@@ -580,7 +590,8 @@ void csv_close(
                             printf(",%d", data_fields[j].net_xxx(at));
                         }
                     }
-                    printf("\n");
+
+                    LINE_BREAK_OUTPUT
                 }
             }    
         }