Moving write errors out of return value into separate API methods.

write(), print(), println() now return size_t (and don't use negative values to signal errors).
Print adds writeError() for checking for write errors, clearWriteError() to reset the flag to false, and a protected setWriteError() for signalling errors.

http://code.google.com/p/arduino/issues/detail?id=598

Author: damellis

Client.cpp

@@ -70,17 +70,23 @@ int Client::connect(IPAddress ip, uint16_t port) {
   return 1;
 }
 
-ssize_t Client::write(uint8_t b) {
+size_t Client::write(uint8_t b) {
   return write(&b, 1);
 }
 
-ssize_t Client::write(const char *str) {
+size_t Client::write(const char *str) {
   return write((const uint8_t *) str, strlen(str));
 }
 
-ssize_t Client::write(const uint8_t *buf, size_t size) {
-  if (_sock == MAX_SOCK_NUM) return -1;
-  if (!send(_sock, buf, size)) return -2;
+size_t Client::write(const uint8_t *buf, size_t size) {
+  if (_sock == MAX_SOCK_NUM) {
+    setWriteError();
+    return 0;
+  }
+  if (!send(_sock, buf, size)) {
+    setWriteError();
+    return 0;
+  }
   return size;
 }
 

Client.h

@@ -12,9 +12,9 @@ class Client : public Stream {
   uint8_t status();
   int connect(IPAddress ip, uint16_t port);
   int connect(const char *host, uint16_t port);
-  virtual ssize_t write(uint8_t);
-  virtual ssize_t write(const char *str);
-  virtual ssize_t write(const uint8_t *buf, size_t size);
+  virtual size_t write(uint8_t);
+  virtual size_t write(const char *str);
+  virtual size_t write(const uint8_t *buf, size_t size);
   virtual int available();
   virtual int read();
   virtual int read(uint8_t *buf, size_t size);

IPAddress.cpp

@@ -42,15 +42,15 @@ bool IPAddress::operator==(const uint8_t* addr)
     return memcmp(addr, _address, sizeof(_address)) == 0;
 }
 
-ssize_t IPAddress::printTo(Print& p) const
+size_t IPAddress::printTo(Print& p) const
 {
-    ssize_t n = 0, t;
+    size_t n = 0;
     for (int i =0; i < 3; i++)
     {
-        if ((t = p.print(_address[i], DEC)) > 0) n += t;
-        if ((t = p.print('.')) > 0) n+= t;
+        n += p.print(_address[i], DEC);
+        n += p.print('.');
     }
-    if ((t = p.print(_address[3], DEC)) > 0) n += t;
+    n += p.print(_address[3], DEC);
     return n;
 }
 

IPAddress.h

@@ -60,7 +60,7 @@ class IPAddress : public Printable {
     IPAddress& operator=(const uint8_t *address);
     IPAddress& operator=(uint32_t address);
 
-    virtual ssize_t printTo(Print& p) const;
+    virtual size_t printTo(Print& p) const;
 
     friend class EthernetClass;
     friend class UDP;

Server.cpp

@@ -67,19 +67,19 @@ Client Server::available()
   return Client(MAX_SOCK_NUM);
 }
 
-ssize_t Server::write(uint8_t b) 
+size_t Server::write(uint8_t b) 
 {
   write(&b, 1);
 }
 
-ssize_t Server::write(const char *str) 
+size_t Server::write(const char *str) 
 {
   write((const uint8_t *)str, strlen(str));
 }
 
-ssize_t Server::write(const uint8_t *buffer, size_t size) 
+size_t Server::write(const uint8_t *buffer, size_t size) 
 {
-  ssize_t n = 0;
+  size_t n = 0;
 
   accept();
 

Server.h

@@ -14,9 +14,9 @@ public Print {
   Server(uint16_t);
   Client available();
   void begin();
-  virtual ssize_t write(uint8_t);
-  virtual ssize_t write(const char *str);
-  virtual ssize_t write(const uint8_t *buf, size_t size);
+  virtual size_t write(uint8_t);
+  virtual size_t write(const char *str);
+  virtual size_t write(const uint8_t *buf, size_t size);
 };
 
 #endif

Udp.cpp

@@ -102,18 +102,18 @@ int UDP::endPacket()
   return sendUDP(_sock);
 }
 
-ssize_t UDP::write(uint8_t byte)
+size_t UDP::write(uint8_t byte)
 {
   return write(&byte, 1);
 }
 
-ssize_t UDP::write(const char *str)
+size_t UDP::write(const char *str)
 {
   size_t len = strlen(str);
   return write((const uint8_t *)str, len);
 }
 
-ssize_t UDP::write(const uint8_t *buffer, size_t size)
+size_t UDP::write(const uint8_t *buffer, size_t size)
 {
   uint16_t bytes_written = bufferData(_sock, _offset, buffer, size);
   _offset += bytes_written;

Udp.h

@@ -67,11 +67,11 @@ class UDP : public Stream {
   // Returns 1 if the packet was sent successfully, 0 if there was an error
   int endPacket();
   // Write a single byte into the packet
-  virtual ssize_t write(uint8_t);
+  virtual size_t write(uint8_t);
   // Write a string of characters into the packet
-  virtual ssize_t write(const char *str);
+  virtual size_t write(const char *str);
   // Write size bytes from buffer into the packet
-  virtual ssize_t write(const uint8_t *buffer, size_t size);
+  virtual size_t write(const uint8_t *buffer, size_t size);
 
   // Start processing the next available incoming packet
   // Returns the size of the packet in bytes, or 0 if no packets are available