Errors when compiling the GSM SMS receive example from the Arduino IDE I want to receive SMS and check whether the character is 'y' or 'n'. If it is 'y', set a pin to high so that a light glows. I thought I could use the example code given in the Arduino IDE for receiving SMS, but when I compile (without connecting the board, using ctrl+r) it shows the following errors:

Arduino: 1.8.1 (Windows 7), Board: "Arduino/Genuino Uno"

In file included from F:\Arduino\libraries\GSM\src/GSM.h:46:0,
                 from F:\Arduino\libraries\GSM\examples\ReceiveSMS\ReceiveSMS.ino:21:
F:\Arduino\libraries\GSM\src/GSM3ShieldV1BandManagement.h:49:125: warning: 'typedef' was ignored in this declaration
 typedef enum GSM3GSMBand {UNDEFINED, EGSM_MODE, DCS_MODE, PCS_MODE, EGSM_DCS_MODE, GSM850_PCS_MODE, GSM850_EGSM_DCS_PCS_MODE};
                                                                                                                             ^
F:\Arduino\libraries\GSM\examples\ReceiveSMS\ReceiveSMS.ino: In function 'void setup()':
F:\Arduino\libraries\GSM\examples\ReceiveSMS\ReceiveSMS.ino:47:34: warning: deprecated conversion from string constant to 'char*' [-Wwrite-strings]
     if (gsmAccess.begin(PINNUMBER) == GSM_READY) {
                                  ^
Sketch uses 13322 bytes (41%) of program storage space. Maximum is 32256 bytes.
Global variables use 996 bytes (48%) of dynamic memory, leaving 1052 bytes for local variables. Maximum is 2048 bytes.
An error occurred while uploading the sketch
This report would have more information with
"Show verbose output during compilation"
option enabled in File -&gt; Preferences.


Please help me rectify the error. 

I use a SIM900 GSM board. I connect the tx and rx of the GSM board to the Arduino's tx and rx.
Those are warnings, not errors.  The code should have compiled and be able to flash.