diff --git a/src/lib-fd.c b/src/lib-fd.c
index 32ad9fe..67cdc7d 100644
--- a/src/lib-fd.c
+++ b/src/lib-fd.c
@@ -97,10 +97,10 @@ static int     (*close_orig)   (int fd);
             && _zz_mustwatch(file)) \
         { \
             if(oflag & O_CREAT) \
-                debug(STR(fn) "(\"%s\", %i, %i) = %i", \
-                      file, oflag, mode, ret); \
+                debug("%s(\"%s\", %i, %i) = %i", \
+                      __func__, file, oflag, mode, ret); \
             else \
-                debug(STR(fn) "(\"%s\", %i) = %i", file, oflag, ret); \
+                debug("%s(\"%s\", %i) = %i", __func__, file, oflag, ret); \
             _zz_register(ret); \
         } \
     } while(0)
@@ -128,7 +128,7 @@ int accept(int sockfd, struct sockaddr *addr, SOCKLEN_T *addrlen)
 
     if(ret >= 0)
     {
-        debug("accept(%i, %p, %p) = %i", sockfd, addr, addrlen, ret);
+        debug("%s(%i, %p, %p) = %i", __func__, sockfd, addr, addrlen, ret);
         _zz_register(ret);
     }
 
@@ -146,7 +146,7 @@ int socket(int domain, int type, int protocol)
 
     if(ret >= 0)
     {
-        debug("socket(%i, %i, %i) = %i", domain, type, protocol, ret);
+        debug("%s(%i, %i, %i) = %i", __func__, domain, type, protocol, ret);
         _zz_register(ret);
     }
 
@@ -171,14 +171,14 @@ int recvfrom(int s,  void  *buf,  size_t len, int flags,
         _zz_addpos(s, ret);
 
         if(ret >= 4)
-            debug("%s(%i, %p, %li) = %i \"%c%c%c%c...", __FUNCTION__, s, buf,
+            debug("%s(%i, %p, %li) = %i \"%c%c%c%c...", __func__, s, buf,
                   (long int)len, ret, b[0], b[1], b[2], b[3]);
         else
-            debug("%s(%i, %p, %li) = %i \"%c...", __FUNCTION__, s, buf,
+            debug("%s(%i, %p, %li) = %i \"%c...", __func__, s, buf,
                   (long int)len, ret, b[0]);
     }
     else
-        debug("%s(%i, %p, %li) = %i", __FUNCTION__, s, buf, (long int)len, ret);
+        debug("%s(%i, %p, %li) = %i", __func__, s, buf, (long int)len, ret);
 
     return ret;
 }
@@ -216,14 +216,14 @@ ssize_t read(int fd, void *buf, size_t count)
         _zz_addpos(fd, ret);
 
         if(ret >= 4)
-            debug("read(%i, %p, %li) = %i \"%c%c%c%c...", fd, buf,
+            debug("%s(%i, %p, %li) = %i \"%c%c%c%c...", __func__, fd, buf,
                   (long int)count, ret, b[0], b[1], b[2], b[3]);
         else
-            debug("read(%i, %p, %li) = %i \"%c...", fd, buf,
+            debug("%s(%i, %p, %li) = %i \"%c...", __func__, fd, buf,
                   (long int)count, ret, b[0]);
     }
     else
-        debug("read(%i, %p, %li) = %i", fd, buf, (long int)count, ret);
+        debug("%s(%i, %p, %li) = %i", __func__, fd, buf, (long int)count, ret);
 
     offset_check(fd);
     return ret;
@@ -238,7 +238,7 @@ ssize_t readv(int fd, const struct iovec *iov, int count)
     if(!_zz_ready || !_zz_iswatched(fd) || _zz_disabled)
         return ret;
 
-    debug("readv(%i, %p, %i) = %li", fd, iov, count, (long int)ret);
+    debug("%s(%i, %p, %i) = %li", __func__, fd, iov, count, (long int)ret);
 
     while(ret > 0)
     {
@@ -278,15 +278,15 @@ ssize_t pread(int fd, void *buf, size_t count, off_t offset)
         _zz_setpos(fd, curoff);
 
         if(ret >= 4)
-            debug("pread(%i, %p, %li, %li) = %i \"%c%c%c%c...", fd, buf,
+            debug("%s(%i, %p, %li, %li) = %i \"%c%c%c%c...", __func__, fd, buf,
                   (long int)count, (long int)offset, ret,
                   b[0], b[1], b[2], b[3]);
         else
-            debug("pread(%i, %p, %li, %li) = %i \"%c...", fd, buf,
+            debug("%s(%i, %p, %li, %li) = %i \"%c...", __func__, fd, buf,
                   (long int)count, (long int)offset, ret, b[0]);
     }
     else
-        debug("pread(%i, %p, %li, %li) = %i", fd, buf,
+        debug("%s(%i, %p, %li, %li) = %i", __func__, fd, buf,
               (long int)count, (long int)offset, ret);
 
     return ret;
@@ -299,8 +299,8 @@ ssize_t pread(int fd, void *buf, size_t count, off_t offset)
         ret = ORIG(fn)(fd, offset, whence); \
         if(!_zz_ready || !_zz_iswatched(fd) || _zz_disabled) \
             return ret; \
-        debug(STR(fn)"(%i, %lli, %i) = %lli", \
-              fd, (long long int)offset, whence, (long long int)ret); \
+        debug("%s(%i, %lli, %i) = %lli", __func__, fd, \
+              (long long int)offset, whence, (long long int)ret); \
         if(ret != (off_t)-1) \
             _zz_setpos(fd, ret); \
     } while(0)
@@ -334,7 +334,7 @@ int close(int fd)
     if(!_zz_ready || !_zz_iswatched(fd) || _zz_disabled)
         return ret;
 
-    debug("close(%i) = %i", fd, ret);
+    debug("%s(%i) = %i", __func__, fd, ret);
     _zz_unregister(fd);
 
     return ret;
diff --git a/src/lib-load.h b/src/lib-load.h
index 4f11f6d..61506b0 100644
--- a/src/lib-load.h
+++ b/src/lib-load.h
@@ -13,9 +13,19 @@
  */
 
 /*
- *  preload.h: preloaded library functions
+ *  lib-load.h: preloaded library functions
  */
 
+/* The __func__ macro to get the current function name */
+#if __STDC_VERSION__ < 199901L
+#   if __GNUC__ >= 2
+#       define __func__ __FUNCTION__
+#   else
+#       define __func__ "<?>"
+#   endif
+#endif
+
+/* Symbol loading stuff */
 #define STR(x) #x
 #define ORIG(x) x##_orig
 
diff --git a/src/lib-mem.c b/src/lib-mem.c
index bce75f6..05c94ed 100644
--- a/src/lib-mem.c
+++ b/src/lib-mem.c
@@ -212,17 +212,17 @@ int nbmaps = 0;
             _zz_setpos(fd, oldpos); \
             ret = b; \
             if(length >= 4) \
-                debug(STR(fn)"(%p, %li, %i, %i, %i, %lli) = %p \"%c%c%c%c...", \
-                      start, (long int)length, prot, flags, fd, \
+                debug("%s(%p, %li, %i, %i, %i, %lli) = %p \"%c%c%c%c...", \
+                      __func__, start, (long int)length, prot, flags, fd, \
                       (long long int)offset, ret, b[0], b[1], b[2], b[3]); \
             else \
-                debug(STR(fn)"(%p, %li, %i, %i, %i, %lli) = %p \"%c...", \
-                      start, (long int)length, prot, flags, fd, \
+                debug("%s(%p, %li, %i, %i, %i, %lli) = %p \"%c...", \
+                      __func__, start, (long int)length, prot, flags, fd, \
                       (long long int)offset, ret, b[0]); \
         } \
         else \
-            debug(STR(fn)"(%p, %li, %i, %i, %i, %lli) = %p", \
-                  start, (long int)length, prot, flags, fd, \
+            debug("%s(%p, %li, %i, %i, %i, %lli) = %p", \
+                  __func__, start, (long int)length, prot, flags, fd, \
                   (long long int)offset, ret); \
     } while(0)
 
@@ -254,7 +254,7 @@ int munmap(void *start, size_t length)
         ret = munmap_orig(maps[i + 1], length);
         maps[i] = NULL;
         maps[i + 1] = NULL;
-        debug("munmap(%p, %li) = %i", start, (long int)length, ret);
+        debug("%s(%p, %li) = %i", __func__, start, (long int)length, ret);
         return ret;
     }
 
@@ -284,17 +284,18 @@ kern_return_t map_fd(int fd, vm_offset_t offset, vm_offset_t *addr,
          * closed (unlike mmap, which returns a persistent buffer). */
 
         if(numbytes >= 4)
-           debug("map_fd(%i, %lli, &%p, %i, %lli) = %i \"%c%c%c%c", fd,
-                 (long long int)offset, (void *)*addr, (int)find_space,
+           debug("%s(%i, %lli, &%p, %i, %lli) = %i \"%c%c%c%c", __func__,
+                 fd, (long long int)offset, (void *)*addr, (int)find_space,
                  (long long int)numbytes, ret, b[0], b[1], b[2], b[3]);
         else
-           debug("map_fd(%i, %lli, &%p, %i, %lli) = %i \"%c", fd,
+           debug("%s(%i, %lli, &%p, %i, %lli) = %i \"%c", __func__, fd,
                  (long long int)offset, (void *)*addr, (int)find_space,
                  (long long int)numbytes, ret, b[0]);
     }
     else
-        debug("map_fd(%i, %lli, &%p, %i, %lli) = %i", fd, (long long int)offset,
-              (void *)*addr, (int)find_space, (long long int)numbytes, ret);
+        debug("%s(%i, %lli, &%p, %i, %lli) = %i", __func__, fd,
+              (long long int)offset, (void *)*addr, (int)find_space,
+              (long long int)numbytes, ret);
 
     return ret;
 }
diff --git a/src/lib-signal.c b/src/lib-signal.c
index 9a2e641..2fbe91f 100644
--- a/src/lib-signal.c
+++ b/src/lib-signal.c
@@ -94,7 +94,7 @@ SIG_T signal(int signum, SIG_T handler)
 
     ret = signal_orig(signum, isfatal(signum) ? SIG_DFL : handler);
 
-    debug("signal(%i, %p) = %p", signum, handler, ret);
+    debug("%s(%i, %p) = %p", __func__, signum, handler, ret);
 
     return ret;
 }
@@ -118,7 +118,7 @@ int sigaction(int signum, const struct sigaction *act, struct sigaction *oldact)
     else
         ret = sigaction_orig(signum, act, oldact);
 
-    debug("sigaction(%i, %p, %p) = %i", signum, act, oldact, ret);
+    debug("%s(%i, %p, %p) = %i", __func__, signum, act, oldact, ret);
 
     return ret;
 }
diff --git a/src/lib-stream.c b/src/lib-stream.c
index 1cbec32..8ebb9a1 100644
--- a/src/lib-stream.c
+++ b/src/lib-stream.c
@@ -102,7 +102,7 @@ int            (*__srefill_orig) (FILE *fp);
         { \
             int fd = fileno(ret); \
             _zz_register(fd); \
-            debug(STR(fn) "(\"%s\", \"%s\") = [%i]", path, mode, fd); \
+            debug("%s(\"%s\", \"%s\") = [%i]", __func__, path, mode, fd); \
         } \
     } while(0)
 
@@ -142,7 +142,8 @@ FILE *freopen(const char *path, const char *mode, FILE *stream)
     }
 
     if(disp)
-        debug("freopen(\"%s\", \"%s\", [%i]) = [%i]", path, mode, fd0, fd1);
+        debug("%s(\"%s\", \"%s\", [%i]) = [%i]", __func__,
+              path, mode, fd0, fd1);
 
     return ret;
 }
@@ -180,7 +181,7 @@ FILE *freopen(const char *path, const char *mode, FILE *stream)
         _zz_disabled = 1; \
         ret = ORIG(fn)(stream, offset, whence); \
         _zz_disabled = 0; \
-        debug(STR(fn)"([%i], %lli, %i) = %i", \
+        debug("%s([%i], %lli, %i) = %i", __func__, \
               fd, (long long int)offset, whence, ret); \
         FSEEK_FUZZ(fn2) \
     } while(0)
@@ -212,7 +213,7 @@ void rewind(FILE *stream)
     _zz_disabled = 1;
     rewind_orig(stream);
     _zz_disabled = 0;
-    debug("rewind([%i])", fd);
+    debug("%s([%i])", __func__, fd);
 
 #if defined HAVE___SREFILL /* Don't fuzz or seek if we have __srefill() */
 #else
@@ -240,8 +241,8 @@ size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream)
     _zz_disabled = 1;
     ret = fread_orig(ptr, size, nmemb, stream);
     _zz_disabled = 0;
-    debug("fread(%p, %li, %li, [%i]) = %li",
-          ptr, (long int)size, (long int)nmemb, fd, (long int)ret);
+    debug("%s(%p, %li, %li, [%i]) = %li", __func__, ptr,
+          (long int)size, (long int)nmemb, fd, (long int)ret);
 
 #if defined HAVE___SREFILL /* Don't fuzz or seek if we have __srefill() */
 #else
@@ -287,9 +288,9 @@ size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream)
         _zz_disabled = 0; \
         FGETC_FUZZ \
         if(ret >= 0x20 && ret <= 0x7f) \
-            debug(STR(fn)"([%i]) = 0x%02x '%c'", fd, ret, (char)ret); \
+            debug("%s([%i]) = 0x%02x '%c'", __func__, fd, ret, (char)ret); \
         else \
-            debug(STR(fn)"([%i]) = 0x%02x", fd, ret); \
+            debug("%s([%i]) = 0x%02x", __func__, fd, ret); \
     } while(0)
 
 #undef getc /* can be a macro; we don’t want that */
@@ -361,7 +362,7 @@ char *fgets(char *s, int size, FILE *stream)
     }
 #endif
 
-    debug("fgets(%p, %i, [%i]) = %p", s, size, fd, ret);
+    debug("%s(%p, %i, [%i]) = %p", __func__, s, size, fd, ret);
     return ret;
 }
 
@@ -393,9 +394,9 @@ int ungetc(int c, FILE *stream)
 #endif
 
     if(ret >= 0x20 && ret <= 0x7f)
-        debug("ungetc(0x%02x, [%i]) = 0x%02x '%c'", c, fd, ret, ret);
+        debug("%s(0x%02x, [%i]) = 0x%02x '%c'", __func__, c, fd, ret, ret);
     else
-        debug("ungetc(0x%02x, [%i]) = 0x%02x", c, fd, ret);
+        debug("%s(0x%02x, [%i]) = 0x%02x", __func__, c, fd, ret);
     return ret;
 }
 
@@ -411,7 +412,7 @@ int fclose(FILE *fp)
     _zz_disabled = 1;
     ret = fclose_orig(fp);
     _zz_disabled = 0;
-    debug("fclose([%i]) = %i", fd, ret);
+    debug("%s([%i]) = %i", __func__, fd, ret);
     _zz_unregister(fd);
 
     return ret;
@@ -465,10 +466,10 @@ int fclose(FILE *fp)
             } \
         } \
         if(need_delim) \
-            debug(STR(fn) "(%p, %p, 0x%02x, [%i]) = %li", \
+            debug("%s(%p, %p, 0x%02x, [%i]) = %li", __func__, \
                   lineptr, n, delim, fd, (long int)ret); \
         else \
-            debug(STR(fn) "(%p, %p, [%i]) = %li", \
+            debug("%s(%p, %p, [%i]) = %li", __func__, \
                   lineptr, n, fd, (long int)ret); \
         return ret; \
     } while(0)
@@ -544,7 +545,7 @@ char *fgetln(FILE *stream, size_t *len)
     ret = fuzz->tmp;
 #endif
 
-    debug("fgetln([%i], &%li) = %p", fd, (long int)*len, ret);
+    debug("%s([%i], &%li) = %p", __func__, fd, (long int)*len, ret);
     return ret;
 }
 #endif
@@ -574,7 +575,7 @@ int __srefill(FILE *fp)
     }
 
     if(!_zz_disabled)
-        debug("__srefill([%i]) = %i", fd, ret);
+        debug("%s([%i]) = %i", __func__, fd, ret);
 
     return ret;
 }