在这段代码中, ftell(dir) 返回 0。但是当我使用 fread_s() 阅读时,所有预期的文本都出现了。知道为什么 ftell() 在这种情况下返回 0 吗?
FILE* dir = _popen("dir", "rt");
if (dir == NULL) {
send(socket, "0", 10, 0);
cerr << "\nerror opening dir" << endl;
return;
}
int r = fseek(dir, 0, SEEK_END);
if (r != 0) {
send(socket, "0", 10, 0);
cerr << "\nerror seeking end" << endl;
return;
}
long dirLength = ftell(dir);
fseek(dir, 0, SEEK_SET);
cout << "dirLength " << dirLength << endl;
char dirListLength[10];
memset(dirListLength, 0, 10);
sprintf_s(dirListLength, 10, "%u", dirLength);
cout << "dirListLength " << dirListLength << endl;
send(socket, dirListLength, 10, 0);
long sentDir = 0;
char buffer[BUFFER_SIZE];
memset(buffer, 0, BUFFER_SIZE);
while (fread_s(buffer, BUFFER_SIZE, sizeof(char), BUFFER_SIZE, dir) > 0) {
send(socket, buffer, BUFFER_SIZE, 0);
cout << buffer << endl;
cout << 1 << endl;
memset(buffer, 0, BUFFER_SIZE);
}
_pclose(dir);