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Full Discussion: Nanosleep in signal call
Top Forums Programming Nanosleep in signal call Post 302963489 by jim mcnamara on Thursday 31st of December 2015 10:05:18 AM
Old 12-31-2015
I am guessing you do not want signal handling at all, other than cleaning up open files and buffers when your app gets a SIGTERM, for example.

Why? read.

This says you are designing an app that has an associated process that is doing reads.
Consider another standard IPC model instead. They are a much better choice if you must do reads in one process.

Overview:
http://www.tldp.org/LDP/tlk/ipc/ipc.html

Pipes are great, they are very like playing with files.
The GNU C Library: Creating a Pipe


Shared memory among processes is also a great feature. You can atomically set a variable in shared memory, then execute a read into a buffer there.
Use semaphores for traffic control. This one is straightforward to get right.
shm_overview(7) - Linux manual page

Overall, consider getting a copy of 3rd Edition of Stevens & Rago 'Advanced Programming in the UNIX Environment'. Michael Kerrisk has done the same thing purely for Linux - 'The LINUX Programming Interface'

Both of these have great examples of all of IPC, and explain how not to shoot yourself in the foot. Like you seemed to want to do. They fully cover signals as well, if you cannot change your system design, and have to continue into the Dark Side.

Have a good New Year!

Last edited by jim mcnamara; 12-31-2015 at 11:11 AM..
 

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USLEEP(3)						   BSD Library Functions Manual 						 USLEEP(3)

NAME
usleep -- suspend thread execution for an interval measured in microseconds LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <unistd.h> int usleep(useconds_t microseconds); DESCRIPTION
The usleep() function suspends execution of the calling thread until either microseconds microseconds have elapsed or a signal is delivered to the thread and its action is to invoke a signal-catching function or to terminate the process. System activity or limitations may lengthen the sleep by an indeterminate amount. This function is implemented using nanosleep(2) by pausing for microseconds microseconds or until a signal occurs. Consequently, in this implementation, sleeping has no effect on the state of process timers, and there is no special handling for SIGALRM. Also, this implementa- tion does not put a limit on the value of microseconds (other than that limited by the size of the useconds_t type); some other platforms require it to be less than one million. NOTE
The usleep() function is obsolescent. Use nanosleep(2) instead. RETURN VALUES
The usleep() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error. ERRORS
The usleep() function will fail if: [EINTR] A signal was delivered to the process and its action was to invoke a signal-catching function. SEE ALSO
nanosleep(2), sleep(3) HISTORY
The usleep() function appeared in 4.3BSD. BSD
February 13, 1998 BSD
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