I'm working on Linux OS (Suse/redhat) and trying to format a linux partition from a c program.
Is there a way to do this without using :
'system ("mkfs.ext4 /dev/sdxy")'

Certainly not a system call - the kernel couldn't care less. Supporting every new filesystem that comes along ?. Not likely - that's userspace functionality.
Precisely the reason fuse was merged.

raj010, why would using system() not possible in your case?

system command will be executed in bash.....i don't want to use bash shell

OK, then exec the program you want directly (actually fork()/exec() the program you want) without calling the shell. Yes, for many purposes, using bash is a bad idea, certainly not using it is way more secure..you don't want to run their profile with your root authority for example.. In order to be sure, you clear the environment (after the fork, in the child) and exec the program you want using the complete path name.

Remember that in Unix, you have to do all substitution that the shell would otherwise do. So you would want (pseudocode, use your own man pages)..

pid_t child;

if((child=fork())== 0) { // in child
// in a loop close everything but fd 0,1,2. http://www.linuxquestions.org/questi...iptors-571188/
execle("/path/mke2fs", "mke2fs","/dev/partition",NULL, NULL); // Second null is environment
perror("whoops, exec of mke2fs failed");
exit(1);
}
if(child == -1) {
perror("fork failed");
exit(1);
}
waitpid(child,.......);

And so forth. That allows you to call another program without using bash, more or less, for security reasons. Of course, you should be sure that you are calling from the system library. You might consider checking the ownership of the program you want to exec to increase the chance it is not a trojan.