计算文件的大小

#include <stdlib.h>
#include <stdio.h>

unsigned int filesize(FILE *fp)
{
        unsigned int fSet,fEnd,filelen;


        fseek(fp,0,SEEK_SET);  
          fSet = ftell(fp);   

        fseek(fp,0,SEEK_END);  
          fEnd = ftell(fp);   
       
        rewind(fp);

        return (filelen = fEnd - fSet);  
}

int main(void)
{
	FILE * fp;
	int sign_close = 0;
        int len = 0; 
	fp = fopen("pm.xml","r");
	if(NULL == fp)
		{
		perror("pm open fail:");
		}
	else
		{
		len = filesize(fp);
                printf("file len is %i",len);
		}
	sign_close = fclose(fp);
	if(0 == sign_close)
		{
		printf("close success\n");
		}
    
	return 0;

}