improve error handling api (#348)

app/utils/dirs.c

@@ -243,7 +243,8 @@ struct dir_path {
 static int rmdir_w_msg(const char *path, int *err) {
 #ifdef WIN32
   if (!RemoveDirectoryA(path)) {
-    zsv_win_printLastError();
+    zsv_perror(path);
+    // zsv_win_printLastError();
     *err = 1;
   }
 #else

app/utils/file.c

@@ -14,6 +14,7 @@
 #include <fcntl.h>  // open
 
 #include <zsv/utils/dirs.h>
+#include <zsv/utils/os.h>
 #include <zsv/utils/file.h>
 
 /**
@@ -29,15 +30,20 @@ char *zsv_get_temp_filename(const char *prefix) {
   TCHAR lpTempPathBuffer[MAX_PATH];
   DWORD dwRetVal = GetTempPath(MAX_PATH,          // length of the buffer
                                lpTempPathBuffer); // buffer for path
-  if (dwRetVal > 0 && dwRetVal < MAX_PATH) {
+  if (!(dwRetVal > 0 && dwRetVal < MAX_PATH))
+    zsv_perror("GetTempPath");
+  else {
     char szTempFileName[MAX_PATH];
     UINT uRetVal = GetTempFileName(lpTempPathBuffer, // directory for tmp files
                                    TEXT(prefix),     // temp file name prefix
                                    0,                // create unique name
                                    szTempFileName);  // buffer for name
     if (uRetVal > 0)
       return strdup(szTempFileName);
+    zsv_perror(lpTempPathBuffer);
+    fprintf(stderr, "  prefix: %s\n", prefix);
   }
+
   return NULL;
 }
 #else

app/utils/os.c

@@ -72,7 +72,7 @@ int zsv_replace_file(const void *src, const void *dest) {
   return 1; // fail
 }
 
-void zsv_win_printLastError(void) {
+static void zsv_win_printLastError(void) {
   DWORD dw = GetLastError();
   LPVOID lpMsgBuf;
   LPVOID lpDisplayBuf;

include/zsv/utils/os.h

@@ -28,8 +28,8 @@ int zsv_replace_file(const void *src, const void *dest);
 
 /**
  * Windows does not have perror(), so we define our own printLastError()
+void zsv_win_printLastError(const char *prefix);
  */
-void zsv_win_printLastError();
 
 #endif