一、判断文件是否存在
#ifdef WIN32
#include <io.h> //C (Windows) access
#else
#include <unistd.h> //C (Linux) access
#endif
#include <fstream> //C++ fstream
#ifdef WIN32
#include <Windows.h> //Windows API FindFirstFile
#include <Shlwapi.h>
#pragma comment(lib, "shlwapi.lib") //Windows API PathFileExists
#endif
#include <boost/filesystem.hpp> //boost
using namespace std;
int main()
{
char file_name[] = "D://aa.txt";
//C run in windows and linux
if ( 0 == access(file_name, 0) ) cout<<"access(): file exist."<<endl;
else cout<<"access(): file not exist."<<endl;
//C++ run in windows and linux
fstream fs;
fs.open(file_name, ios::in);
if (fs) cout<<"fstream: file exist."<<endl;
else cout<<"fstream: file not exist."<<endl;
fs.close();
//Windows API run in windows
#ifdef WIN32
WIN32_FIND_DATA wfd;
HANDLE hFind = FindFirstFile(file_name, &wfd);
if ( INVALID_HANDLE_VALUE != hFind ) cout<<"FindFirstFile: file exist."<<endl;
else cout<<"FindFirstFile: file not exist."<<endl;
CloseHandle(hFind);
if ( PathFileExists(file_name) ) cout<<"PathFileExists: file exist."<<endl;
else cout<<"PathFileExists: file not exist."<<endl;
if ( INVALID_FILE_ATTRIBUTES != GetFileAttributes(file_name) ) cout<<"GetFileAttributes: file exist."<<endl;
else cout<<"GetFileAttributes: file not exist."<<endl;
if ( INVALID_HANDLE_VALUE != CreateFile(file_name, GENERIC_READ, 0, NULL, OPEN_EXISTING, NULL, NULL) ) cout<<"CreateFile: file exist."<<endl;
else cout<<"CreateFile: file not exist."<<endl;
#endif
//boost run in windows and linux
boost::filesystem::path path_file(file_name);
if ( boost::filesystem::exists(path_file) &&
boost::filesystem::is_regular_file(path_file) ) cout<<"boost: file exist."<<endl;
else cout<<"boost: file not exist."<<endl;
return 0;
}二、判断目录是否存在
#ifdef WIN32
#include <io.h> //C (Windows) access
#else
#include <unistd.h> //C (Linux) access
#endif
#ifdef WIN32
#include <Windows.h> //Windows API FindFirstFile
#include <Shlwapi.h>
#pragma comment(lib, "shlwapi.lib") //Windows API PathFileExists
#endif
#include <boost/filesystem.hpp> //boost
using namespace std;
int main()
{
char file_name[] = "D://b";
//C run in windows and linux
if ( 0 == access(file_name, 0) ) cout<<"access(): path exist."<<endl;
else cout<<"access(): path not exist."<<endl;
//Windows API run in windows
#ifdef WIN32
WIN32_FIND_DATA wfd;
HANDLE hFind = FindFirstFile(file_name, &wfd);
if ( INVALID_HANDLE_VALUE != hFind && (wfd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) ) cout<<"FindFirstFile: path exist."<<endl;
else cout<<"FindFirstFile: path not exist."<<endl;
CloseHandle(hFind);
if ( PathFileExists(file_name) ) cout<<"PathFileExists: path exist."<<endl;
else cout<<"PathFileExists: path not exist."<<endl;
if ( INVALID_FILE_ATTRIBUTES != GetFileAttributes(file_name) ) cout<<"GetFileAttributes: path exist."<<endl;
else cout<<"GetFileAttributes: path not exist."<<endl;
#endif
//boost run in windows and linux
boost::filesystem::path path_file(file_name);
if ( boost::filesystem::exists(path_file) &&
boost::filesystem::is_directory(path_file) ) cout<<"boost: path exist."<<endl;
else cout<<"boost: path not exist."<<endl;
return 0;
}三、几种方式比较
1. 精确判断文件和目录的
FindFirstFile() (Windows API, Windows)
boost (boost, Windows and Linux)
2. 不精确判断文件盒目录的
access() (C , Windows and Linux)
PathFileExists() (Windows API , Windows)
GetFileAttributes() (Windows API, Windows)
3. 只能判断文件的
fstream (C++ STL, Windows and Linux)
CreateFile() (Windows API, Windows)
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作者：kanguolaikanguolaik
来源：CSDN
原文：https://blog.csdn.net/guowenyan001/article/details/17259173
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