结构体itimerspec为timer_create的参数无效的参数 [英] struct itimerspec as timer_create's parameter invalid argument

问题描述

我试图POSIX计时器togheter与POSIX信号处理。
当我尝试excecute的code，你可以找到downhere，我得到：

Errore timer_settime：无效的参数

在GAPIL书，那是基于高级Linux编程和Unix网络编程，我读到这可能发生new_value.value您指定一个负的时间值或纳秒数比999999999更高内部时。
但我认为，我已经使用的参数是可以的...

 的#include＆LT;＆string.h中GT;
＃包括LT＆;＆stdio.h中GT;
＃包括LT＆;＆fcntl.h GT;
＃包括LT＆;＆time.h中GT;
＃包括LT＆;＆stdlib.h中GT;
＃包括LT＆;＆errno.h中GT;
＃包括LT＆;＆unistd.h中GT;
＃包括LT＆;＆signal.h中GT;
＃包括LT＆; SYS / types.h中＆GT;
＃包括LT＆; SYS / socket.h中＆GT;
＃包括LT＆; ARPA / inet.h＆GT;
＃包括LT＆; netinet / in.h中＆GT;
＃包括LT＆;＆netdb.h中GT;
＃包括LT＆; SYS / fcntl.h＆GT;
＃包括LT＆; SYS / wait.h＆GT;
＃包括LT＆;＆stdbool.h GT;无效termination_handler（INT正负号）
{
    的printf（计时器斯卡杜托\\ n）;
}诠释的main（）
{
    timer_t定时器1;
    结构的sigevent sigeventStruct;
    sigeventStruct.sigev_notify = SIGEV_SIGNAL;
    sigeventStruct.sigev_signo = 10;
    如果（timer_create（_POSIX_MONOTONIC_CLOCK，＆安培; sigeventStruct，＆安培;定时器1）== -1）
    {
        的printf（Errore timer_create：％S \\ n字符串错误（错误））;
    }
    的printf（timer_create eseguito \\ n）;
    结构itimerspec tempoIniziale;
    tempoIniziale.it_value.tv_nsec = 0;    结构itimerspec tempoFinale;
    tempoFinale.it_value.tv_nsec =千万;    如果（timer_settime（定时器1，0，＆安培; tempoIniziale，＆安培; tempoFinale）== -1）
    {
        的printf（Errore timer_settime：％S \\ n字符串错误（错误））;
    }    结构sigaction的newSigAzione，oldSigAzione;
    newSigAzione.sa_handler = termination_handler;
    //oldSigAzione.sa_handler = termination_handler;
    sigemptyset（安培; newSigAzione.sa_mask）;    newSigAzione.sa_flags = 0;
    的sigaction（SIGEV_SIGNAL，NULL，＆安培; oldSigAzione）;
    如果（oldSigAzione.sa_handler！= SIG_IGN）
    {
        //的sigaction（SIGEV_SIGNAL，newSigAzione，NULL）;
    }
    / *的sigaction（SIGINT，NULL，＆安培; oldSigAzione）;
    如果（oldSigAzione.sa_handler！= SIG_IGN）
      的sigaction（SIGINT，和放大器; newSigAzione，NULL）;
    的sigaction（SIGHUP，NULL，＆安培; oldSigAzione）;
    如果（oldSigAzione.sa_handler！= SIG_IGN）
      的sigaction（SIGHUP，＆安培; newSigAzione，NULL）;
    的sigaction（SIGTERM，NULL，＆安培; oldSigAzione）;
    如果（oldSigAzione.sa_handler！= SIG_IGN）
      的sigaction（SIGTERM，＆安培; newSigAzione，NULL）; * /    / *的sigaction（SIGTERM，＆安培; newSigAzione，NULL）; * /    返回0;
}
 

解决方案

_POSIX_MONOTONIC_CLOCK是一个功能测试宏告诉你单调时钟是否可用在系统上。

可用的时钟IDS你可以通过在Linux上timer_create（）是：

CLOCK_REALTIME
  全系统实时时钟。设置此时钟要求相应的权限。
CLOCK_MONOTONIC
  不能设置时钟和再presents因为一些不确定的起点单调的时间。
CLOCK_PROCESS_CPUTIME_ID
  高分辨率每进程计时器从CPU。
CLOCK_THREAD_CPUTIME_ID
  线程特定的CPU时钟。

您还必须初始化所有在结构的sigevent 成员和结构itimerspec 。
例如。您没有设置 .tv_sec 在structitimer_spec，只有 .tv_nsec ，这导致在这些成员垃圾值。

  ...
memset的（安培; sigeventStruct，0，sizeof的sigeventStruct）;
...
和
结构itimerspec tempoFinale;
memset的（安培; tempoFinale，0，sizeof的tempoFinale）;
tempoFinale.it_value.tv_nsec =千万;
 

I was trying POSIX timers togheter with POSIX signals handling. When I try to excecute the code you can find downhere, I get:

Errore timer_settime: Invalid argument

On GAPIL book, that is based upon Advanced Linux Programming and Unix network programming, I read that this can happen when inside new_value.value you specified a negative time value or a number of nanoseconds higher than 999999999. But I think that parameters I have used are okay...

#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <time.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netdb.h>
#include <sys/fcntl.h>
#include <sys/wait.h>
#include <stdbool.h>

void termination_handler(int signum)
{
    printf("Timer scaduto\n");
}

int main()
{
    timer_t timer1;
    struct sigevent sigeventStruct;
    sigeventStruct.sigev_notify = SIGEV_SIGNAL;
    sigeventStruct.sigev_signo = 10;
    if(timer_create(_POSIX_MONOTONIC_CLOCK, &sigeventStruct, &timer1) == -1)
    {
        printf( "Errore timer_create: %s\n", strerror( errno ) );
    }
    printf("timer_create eseguito\n");
    struct itimerspec tempoIniziale;
    tempoIniziale.it_value.tv_nsec = 0;

    struct itimerspec tempoFinale;
    tempoFinale.it_value.tv_nsec = 10000000;

    if(timer_settime(timer1, 0, &tempoIniziale, &tempoFinale) == -1)
    {
        printf( "Errore timer_settime: %s\n", strerror( errno ) );
    }





    struct sigaction newSigAzione, oldSigAzione;


    newSigAzione.sa_handler = termination_handler;
    //oldSigAzione.sa_handler = termination_handler;
    sigemptyset (&newSigAzione.sa_mask);

    newSigAzione.sa_flags = 0;


    sigaction (SIGEV_SIGNAL, NULL, &oldSigAzione);
    if(oldSigAzione.sa_handler != SIG_IGN)
    {
        //sigaction (SIGEV_SIGNAL, newSigAzione, NULL);
    }
    /*sigaction (SIGINT, NULL, &oldSigAzione);
    if (oldSigAzione.sa_handler != SIG_IGN)
      sigaction (SIGINT, &newSigAzione, NULL);
    sigaction (SIGHUP, NULL, &oldSigAzione);
    if (oldSigAzione.sa_handler != SIG_IGN)
      sigaction (SIGHUP, &newSigAzione, NULL);
    sigaction (SIGTERM, NULL, &oldSigAzione);
    if (oldSigAzione.sa_handler != SIG_IGN)
      sigaction (SIGTERM, &newSigAzione, NULL);*/

    /*sigaction (SIGTERM, &newSigAzione, NULL);*/

    return 0;
}

解决方案

_POSIX_MONOTONIC_CLOCK is a feature test macro that tells you whether monotonic clocks are available on the system.

The available clock ids you can pass to timer_create() on Linux are:

CLOCK_REALTIME
  System-wide realtime clock. Setting this clock requires appropriate privileges.
CLOCK_MONOTONIC
  Clock that cannot be set and represents monotonic time since some unspecified starting point.
CLOCK_PROCESS_CPUTIME_ID
  High-resolution per-process timer from the CPU.
CLOCK_THREAD_CPUTIME_ID
  Thread-specific CPU-time clock.

You must also initialize all the members in struct sigevent and struct itimerspec. E.g. you don't set .tv_sec in the structitimer_spec, only .tv_nsec , which results in garbage values in those members.

...
memset(&sigeventStruct, 0, sizeof sigeventStruct);
...
and 
struct itimerspec tempoFinale;
memset(&tempoFinale, 0, sizeof tempoFinale);
tempoFinale.it_value.tv_nsec = 10000000;

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