linux 定时器使用一

#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); 
}
// 建立信号处理机制
void init_sigaction(void)
{
 struct sigaction tact;  /*信号到了要执行的任务处理函数为doTask*/
 tact.sa_handler = doTask;
 tact.sa_flags = 0; /*初始化信号集*/
 sigemptyset(&tact.sa_mask); /*建立信号处理机制*/
 sigaction(SIGALRM, &tact, NULL);
}
void init_time()
{
 struct itimerval value; /*设定执行任务的时间间隔为30秒0微秒*/
 value.it_value.tv_sec = 30;
 value.it_value.tv_usec = 0; /*设定初始时间计数也为30秒0微秒*/
 value.it_interval = value.it_value; /*设置计时器ITIMER_REAL*/
 setitimer(ITIMER_REAL, &value, NULL);
}
int main()
{
 
 pFile = fopen(runStatusFile, "r+");
 if(pFile == NULL)
 {