ex20

Makefile

@@ -1,5 +1,5 @@
 CFLAGS=-Wall -g
-SOURCES=ex1 ex4 ex6 ex7 ex8 ex9 ex10 ex11 ex12 ex13 ex14 ex15 ex16 ex17 ex18
+SOURCES=ex1 ex4 ex6 ex7 ex8 ex9 ex10 ex11 ex12 ex13 ex14 ex15 ex16 ex17 ex18 ex20
 
 all: $(SOURCES)
 

dbg.h

@@ -0,0 +1,30 @@
+#ifndef __dbg_h__
+#define __dbg_h__
+
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+
+#ifdef NDEBUG
+#define debug(M, ...)
+#else
+#define debug(M, ...) fprintf(stderr, "DEBUG %s:%d: " M "\n", __FILE__, __LINE__, ##__VA_ARGS__)
+#endif
+
+#define clean_errno() (errno == 0 ? "None" : strerror(errno))
+
+#define log_err(M, ...) fprintf(stderr, "[ERROR] (%s:%d: errno %s) " M "\n", __FILE__, __LINE__, clean_errno(), ##__VA_ARGS__)
+
+#define log_warn(M, ...) fprintf(stderr, "[WARN] (%s:%d: errno %s) " M "\n", __FILE__, __LINE__, clean_errno(), ##__VA_ARGS__)
+
+#define log_info(M, ...) fprintf(stderr, "[INFO] (%s:%d) " M "\n", __FILE__, __LINE__, ##__VA_ARGS__)
+
+#define check(A, M, ...) if(!(A)) { log_err(M, ##__VA_ARGS__); errno=0; goto error; }
+
+#define sentinel(M, ...) { log_err(M, ##__VA_ARGS__); errno=0; goto error; }
+
+#define check_mem(A) check((A), "out of memory")
+
+#define check_debug(A, M, ...) if(!(A)) { debug(M, ##__VA_ARGS__); errno=0; goto error; }
+
+#endif

ex20.c

@@ -0,0 +1,117 @@
+#include "dbg.h"
+#include <stdlib.h>
+#include <stdio.h>
+
+
+void test_debug()
+{
+  debug("I have brown hair");
+  debug("I am %d years old", 25);
+}
+
+void test_log_err()
+{
+  log_err("shit's broke");
+  log_err("ther are %d problems in %s", 0, "space");
+}
+
+void test_log_warn()
+{
+  log_warn("you can safely ignore this");
+  log_warn("maybe consider having a look at: %s", "/etc/passwd");
+}
+
+void test_log_info()
+{
+  log_info("this is something");
+  log_info("it happened %f times today", 1.3f);
+}
+
+int test_check(char *file_name)
+{
+  FILE *input = NULL;
+  char *block = NULL;
+
+  block = malloc(100);
+  check_mem(block);
+
+  input = fopen(file_name, "r");
+  check(input, "failed to open %s", file_name);
+
+  free(block);
+  fclose(input);
+  return 0;
+
+error:
+  if(block) free(block);
+  if(input) fclose(input);
+  return -1;
+}
+
+int test_sentinel(int code)
+{
+  char *temp = malloc(100);
+  check_mem(temp);
+
+  switch(code) {
+    case 1:
+      log_info("it worked");
+      break;
+    default:
+      sentinel("I shouldn't run");
+  }
+
+  free(temp);
+  return 0;
+
+error:
+  if(temp) free(temp);
+  return -1;
+}
+
+int test_check_mem()
+{
+  char *test = NULL;
+  check_mem(test);
+
+  free(test);
+  return 1;
+
+error:
+  return -1;
+}
+
+int test_check_debug()
+{
+  int i = 0;
+  check_debug(i != 0, "oops, i was 0");
+
+  return 0;
+
+error:
+  return -1;
+}
+
+int main(int argc, char *argv[])
+{
+  check(argc == 2, "Need an argument");
+
+  test_debug();
+  test_log_err();
+  test_log_warn();
+  test_log_info();
+
+  check(test_check("ex20.c") == 0, "failed with ex20.c");
+  check(test_check(argv[1]) == -1, "failed with argv");
+  check(test_sentinel(1) == 0, "test_sentinel failed");
+  check(test_sentinel(100) == -1, "test_sentinel failed");
+  check(test_check_mem() == -1, "test_check_mem failed");
+  check(test_check_debug() == -1, "test_check_debug failed");
+
+  return 0;
+
+error:
+  return 1;
+}
+
+