如何在Linux中获取C/C++中的用户名？

Question

如何在不使用程序中的环境(getenv,...)的情况下获取实际的"用户名"？

Answer 1

getlogin_r()定义的函数unistd.h返回用户名.有关man getlogin_r更多信息,请参阅

它的签名是:

int getlogin_r(char *buf, size_t bufsize);

不用说,这个函数可以很容易地在C或C++中调用.

Answer 2

来自http://www.unix.com/programming/21041-getting-username-c-program-unix.html:

/* whoami.c */
#define _PROGRAM_NAME "whoami"
#include <stdlib.h>
#include <pwd.h>
#include <stdio.h>

int main(int argc, char *argv[])
{
  register struct passwd *pw;
  register uid_t uid;
  int c;

  uid = geteuid ();
  pw = getpwuid (uid);
  if (pw)
    {
      puts (pw->pw_name);
      exit (EXIT_SUCCESS);
    }
  fprintf (stderr,"%s: cannot find username for UID %u\n",
       _PROGRAM_NAME, (unsigned) uid);
  exit (EXIT_FAILURE);

}

只需占用主线并将其封装在类中:

class Env{
    public:
    static std::string getUserName()
    {
        uid_t uid = geteuid ();
        struct passwd *pw = getpwuid (uid);
        if (pw)
        {
            return std::string(pw->pw_name);
        }
        return {};
    }
};

仅适用于C:

const char *getUserName()
{
  uid_t uid = geteuid();
  struct passwd *pw = getpwuid(uid);
  if (pw)
  {
    return pw->pw_name;
  }

  return "";
}