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<concept id="GUID-E65D91AE-482F-5592-B83C-0F29126C2EFA" xml:lang="en"><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 &lt;stdio.h&gt;
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 the 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>