c - 将变量添加到文件路径

Question

我获得了用户 ID 以将其添加到文件路径中。但是我在创建文件时遇到了问题。如何将用户标识添加到文件路径？我使用了 strcpy 但这似乎不起作用。这是我的代码。

  mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
  register struct passwd *pw;
  register uid_t uid;
  uid = geteuid ();
  pw = getpwuid (uid);
  char str[1000];
  strcpy(str, "/home/" );
  strcpy(str, pw->pw_name );
  strcpy(str, "/Documents/test.txt" );
  int openFile = creat(str, mode);

Answer 1

三次 strcpy() ？也许你想要:

strcpy(str, "/home/");
strcat(str, pw->pw_name);
strcat(str, "/Documents/test.txt");

?或者更好:

int ret;
ret = snprintf(str, sizeof str, "%s/%s/%s"
   , "/home" , pw->pw_name, "Documents/test.txt");
if (ret >= sizeof str) {... error...}