c语言获取当前程序运行的cpuid

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <syscall.h>

#define ULONG unsigned long
#define CHAR char
#define VOID void
#define gettid()  syscall(SYS_gettid)


ULONG drvgetprocessorid(VOID)
{
    ULONG ultaskcpu=0;
    ULONG uloopi = 0;
    char szFilename[50];
    char cflag=0;    
    CHAR szBuf[512];
    FILE *pstFp=NULL;

    memset(szfilename,0,(ULONG)50);
    snprintf(szfilename,sizeof(szfilename),"/proc/%d/task/%d/stat",getpid(),gettid());
    pstfp=fopen(szfilename,"r");
    if(null==pstfp)
    {
        return 30;
    }
    while(0 ==feof(pstfp))
    {
        if(uloopi == 38)
        {
            fgets(szbuf,sizeof(szbuf),pstfp);
            sscanf(szbuf,"%lu",&ultaskcpu);
            break;
        }    
        cflag=fgetc(pstfp);
        if(‘ ’ == cflag)
        {
            uloopi++;
        }

    }

    fclose(pstfp);
    return ultaskcpu;
    
}