why my chmod fail all the time

[sysabod]

i wrote a little program which made use of the chmod system call
to change my file permissions.Here is my code.

#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>

int main(int argc,char* argv[])
{
	
	if( (chmod(argv[1],S_IWUSR)) == 0)
		printf("change mode operation succeded\n");
	
	
	return 0;
}

i initially set the file permission to 000 by the chmod command in the terminal
then i ran my programm which took command line arguments,howerver,everytime after the execution,i checked out the new permission,it was solely 777(regardless of the mode_t parameter i sepecified).

is there anything wrong with my programme or it is because of the umask system variable ,if it is,how to see it and fix it.

Thanks in advance!

[chrisname]

Are you changing the mode of something you own? If you aren't root, you won't be able to change other people's files.

[sysabod]

Yes, i logged in as a root user,besides i was the one who created that file.
PLUS, the printf statement is executed .

[chrisname]

That's weird. I can't say why that would happen.

[sysabod]

i finally figured it out. I think it is because of the location of the file .

I used my virtual machine(Vmware , the os is Fedora12) to do this experiment and the file to
be tested locates at /mnt/hgfs/LinuxProgramming which is a place used to place shared folders.

I tried to create the file to be tested on a another place like /root and this time i succeeded.

It turns out the file permission is User-write only as i expected.