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<concept xml:lang="en" id="GUID-E65D91AE-482F-5592-B83C-0F29126C2EFA"><title>Using Signals to Handle Exceptions </title><prolog><metadata><keywords/></metadata></prolog><conbody><p>Signals provide an alternative method (to checking return values) of handling exceptions or failures. The following example code demonstrates how you can check the return value for a failure and also how you can register a handler for handling the failure asynchronously: </p> <codeblock id="GUID-49B4A39A-34F5-54D1-AD97-5AD50EFD9786" xml:space="preserve">#include &lt;signal.h&gt;

#include <stdio.h>

int func()

    {

    int success = 1;

    // function logic

    // success == 1  - Indicates that the function logic succeeded

    // success == 0  - Indicates that the function logic failed

    if(success)

        return 0;

    else

        {

        raise(SIGUSR1);

        return -1;

        }

    }

void sighandler(int signum)

    {

    if(signum == SIGUSR1)

        // 'signal' method for checking failure

        printf(“Error: An error occured in func().”);

    else

        printf(“Error: Unknown signal”);

    }

int main(void)

    {

    int retval = 0;

    // When SIGUSR1 arrives, invoke sighandler()

    signal(SIGUSR1,sighandler);

    retval = func();

    if(retval == -1)

        // The return value method used for checking failure

        printf("Error: An error occured in func().");  

    }</codeblock> </conbody><related-links><link href="GUID-66C1493D-5B85-558A-9A39-454E6EBA307B.dita"><linktext>Signal Emulation on Symbian

                Platform</linktext> </link> <link href="GUID-186B9876-2A08-5F23-BB49-49EC34C51507.dita"><linktext>Using Signals to Terminate Processes</linktext> </link> <link href="GUID-6CF8A41B-C2DD-5D57-A71D-6405CE08A06B.dita"><linktext>Using Signals to Handle Asynchronous

                Events</linktext> </link> </related-links></concept>