Important Update:

- SelectableCore:
  - Finish UDP implementation
    - Change UDPsock to UDPserver/client/remote
    - Add OpenUDPserver/client/remote methods
    - Add ReadFrom/WriteToUDP() methods (cannot write to FD)
    - ReadFrom/WriteToFD():
      - return negative bytes on error
      - small delay between consecutive reads/writes
  - Set address correctly on resolve (for UDP or TCP)
  - Improve ReadFrom/WriteToFD() methods (improved timing & error)
  - Improve error reporting on Input/OutputHandle() methods
- CharBufferCore:
  - Standardise ReadFrom/WriteToFD() method
  - Bug fix: Peek/PeekCopy error if Data param not passed
- FileCore
  - Standardise ReadFrom/WriteToFD() method

FileCore.cpp

@@ -185,7 +185,8 @@ int CFileCore::ReadFromFD( int FD, char * Data, int MaxLen )
 {
     int     BytesRead       = 0;
     int     TotalRead       = 0;
-    int     DataRemain      = 0;
+    int     DataRemain      = MaxLen;
+    bool    Error           = false;
 
     // Check if buffer created
     if ((FD == -1) || !Data) {
@@ -193,20 +194,26 @@ int CFileCore::ReadFromFD( int FD, char * Data, int MaxLen )
     }
 
     // Read Data into buffer
-    DataRemain = (MaxLen == -1)? strlen(Data) : MaxLen;
     while (DataRemain)
     {
         // Read from file descriptor
         BytesRead = read( FD, &Data[TotalRead], DataRemain );
-        if (BytesRead <= 0)
+        if (BytesRead <= 0) {
+            Error = true;
+            errno = (!BytesRead)? 0 : errno;        // No error if no bytes written
             break;
+        }
 
         // Update Data Pointers
         TotalRead += BytesRead;
         DataRemain -= BytesRead;
+
+        if (DataRemain) {
+            usleep( 500 );
+        }
     }
 
-    return TotalRead;
+    return (Error)? -TotalRead : TotalRead;         // Report negative total on error
 }
 //---------------------------------------------------------------------------
 
@@ -214,28 +221,34 @@ int CFileCore::WriteToFD( int FD, const char * Data, int Len )
 {
     int     BytesWritten    = 0;
     int     TotalWritten    = 0;
-    int     DataRemain      = 0;
+    int     DataRemain      = (Len != -1)? Len : (Data)? strlen(Data) : 0;
+    bool    Error           = false;
 
     // Check if buffer created
-    if ((FD == -1) || !Data) {
+    if ((FD == -1) || !DataRemain) {
         return 0;
     }
 
     // Read Data into buffer
-    DataRemain = (Len == -1)? strlen(Data) : Len;
     while (DataRemain)
     {
         // Read from file descriptor
         BytesWritten = write( FD, &Data[TotalWritten], DataRemain );
-        if ((BytesWritten <= 0) && (errno != EAGAIN))
+        if ((BytesWritten <= 0) && (errno != EAGAIN)) {
+            Error = true;
+            errno = (!BytesWritten)? 0 : errno;     // No error if no bytes written
             break;
+        }
 
         // Update Data Pointers
         TotalWritten += BytesWritten;
         DataRemain -= BytesWritten;
-    }
 
-    return TotalWritten;
+        if (DataRemain) {
+            usleep( 500 );
+        }
+    }
+    return (Error)? -TotalWritten : TotalWritten;    // Report negative total on error
 }
 //---------------------------------------------------------------------------