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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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NANOSLEEP(2)						      BSD System Calls Manual						      NANOSLEEP(2)

NAME
nanosleep -- suspend process execution for an interval measured in nanoseconds LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <time.h> int nanosleep(const struct timespec *rqtp, struct timespec *rmtp); DESCRIPTION
The nanosleep() system call causes the calling thread to sleep until the time interval specified by rqtp has elapsed. An unmasked signal will cause it to terminate the sleep early, regardless of the SA_RESTART value on the interrupting signal. RETURN VALUES
If the nanosleep() system call returns because the requested time has elapsed, the value returned will be zero. If the nanosleep() system call returns due to the delivery of a signal, the value returned will be -1, and the global variable errno will be set to indicate the interruption. If rmtp is non-NULL, the timespec structure it references is updated to contain the unslept amount (the request time minus the time actually slept). ERRORS
The nanosleep() system call fails if: [EFAULT] Either rqtp or rmtp points to memory that is not a valid part of the process address space. [EINTR] The nanosleep() system call was interrupted by the delivery of a signal. [EINVAL] The rqtp argument specified a nanosecond value less than zero or greater than or equal to 1000 million. [ENOSYS] The nanosleep() system call is not supported by this implementation. SEE ALSO
sigsuspend(2), sleep(3) STANDARDS
The nanosleep() system call conforms to IEEE Std 1003.1b-1993 (``POSIX.1''). BSD
April 17, 1997 BSD
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