HI All:
i am back and find the way to use that,
as following is my code but not all
may be you can try it.

#include <sys/param.h>
#include <sys/mount.h>
#include <errno.h>
#include <string.h>
#include <sys/uio.h>
int main()
{
const char cTestPrag[]="/data/test/Test";
int flag;
mount(need to be mounted,"point mount path,flag,"MNT_RDONLY");

//varible flag you can omit but you will get a waring "have no catch ......"

printf("%s",strerror(errno));
return 0;
}

i think use system() to execute mount. maybe use shell than c.
the unix 95 % use c code to write if you want to be a expert onto
c that i think it is necessary.

thanks All