linux 定時器使用一

#include <sys/time.h>
#include <stdio.h>
#include <unistd.h>
#include <signal.h>
#include <string.h>

static char *runStatusFile   = "/syscfg/etc/runStatusFile";
//static char *runStatusFile   = "runStatusFile";
FILE *pFile = NULL;
char runCountStr[10]={0};
unsigned runCountInt = 0;
char runTimeStr[15]={0};
unsigned runTimeInt = 0;

 

void doTask()
{
 
 pFile = fopen(runStatusFile, "r+");
 /*
 if(NULL == pFile)
 {
  pFile = fopen(runStatusFile,"w+");
  fseek (pFile, 0L, SEEK_SET);
  fwrite("0", sizeof(char), 1, pFile);
  fseek (pFile, 6L, SEEK_SET);
  fwrite("0", sizeof(char), 1, pFile);
 }
 */
 fseek (pFile, 11L, SEEK_SET);
 fread (runTimeStr, sizeof(char), 10, pFile);
 runTimeInt = atoi(runTimeStr);
 runTimeInt += 30;
 fseek (pFile, 11L, SEEK_SET);
 sprintf(runTimeStr,"%d",runTimeInt);
 fwrite(runTimeStr, sizeof(char),10, pFile);
 
 
 /*
 fseek (pFile, 11L, SEEK_SET);
 fread (runTimeStr, sizeof(char), 10, pFile);
 printf("runTimeStr = %s/n",runTimeStr);
 */
 fclose(pFile); 
}

// 建立信號處理機制
void init_sigaction(void)
{
 struct sigaction tact;  /*信號到了要執行的任務處理函數爲doTask*/
 tact.sa_handler = doTask;
 tact.sa_flags = 0; /*初始化信號集*/
 sigemptyset(&tact.sa_mask); /*建立信號處理機制*/
 sigaction(SIGALRM, &tact, NULL);
}

void init_time()
{
 struct itimerval value; /*設定執行任務的時間間隔爲30秒0微秒*/
 value.it_value.tv_sec = 30;
 value.it_value.tv_usec = 0; /*設定初始時間計數也爲30秒0微秒*/
 value.it_interval = value.it_value; /*設置計時器ITIMER_REAL*/
 setitimer(ITIMER_REAL, &value, NULL);
}

int main()
{
 
 pFile = fopen(runStatusFile, "r+");
 if(pFile == NULL)
 {
  pFile = fopen(runStatusFile,"w+");
  fseek (pFile, 0L, SEEK_SET);
  fwrite("0", sizeof(char), 1, pFile);
  fseek (pFile, 11L, SEEK_SET);
  fwrite("0", sizeof(char), 1, pFile);
 }  
 fseek (pFile, 0L, SEEK_SET);
 fread (runCountStr, sizeof(char), 5, pFile);
 runCountInt = atoi(runCountStr);
 runCountInt++;  
 sprintf(runCountStr,"%d",runCountInt);
 fseek (pFile, 0L, SEEK_SET);
 fwrite(runCountStr, sizeof(char), 5, pFile); 
 
 fclose(pFile);
 
 init_sigaction();
 init_time();
 while(1);
 
 return 0;
}