kdb172: How to monitor SIGHUP in QNX 4.xx

Title: How to monitor SIGHUP in QNX 4.xx
Keywords: How to monitor SIGHUP in QNX 4.xx
Date: March 19, 1997
KDB: KDB-172
Revision: 0.00
Author: Support
Distribution: External

Please refer to the signal() function description in the QNX Watcom C Library Reference Manual.

This function, signal(), would be used in detecting when a SIGHUP occurs (carrier detect goes low due to a disconnection).

signal(SIGHUP, CleanUpAfterSighup);

When this occurs your custom handler (CleanUpAfterSighup) would do the housekeeping operations of closing any files that are open, and or go on, to monitor another incoming call.

Pseudo-code snippet:
#include
sig_atomic_t signal_count;

void CleanUpAfterSighup(int sig_number)
{
++signal_count;
}

void main()
{
signal(SIGHUP, CleanUpAfterSighup); /*set own handler to perform a clean up*/

/* …the rest of your application… */
}

Generally examples can be found at the following resources:

  • quics, QSSL has lots of free source in the /usr/free area.
  • You can also post a question on quics, or post to comp.os.qnx newsgroups.

End of KDB-172

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