权限在C中使用popen时出现问题（linux）

Question

I am trying to access /proc/net/dev file with -r--r--r-- 1 root root 0 privileges using popen . The code is as fairly as:

main(){
FILE *f;
f=popen("/proc/net/dev","r");
pclose(f);}

logged in as a root,after compiling & running the program, I get this:

sh: /proc/net/dev: Permission denied.

Can you please help me through this problem? thank you

Answer 1

I think you're looking at this the wrong way, popen is to open a pipe from an application. /proc/net/dev is not an application but is a file. Try looking at fopen instead.

f=fopen("/proc/net/dev", "r");
fclose(f);

Answer 2

popen() is for opening a pipe to another process, the path provided must be to an executable file, not a device entry. You probably want open() or fopen() instead.

Answer 3

use read; for more info type man read in a terminal