C/C++判断文件/文件夹是否存在
2014-02-28 18:05
621 查看
原文链接,感谢原作者
在使用PathFileExists输入参数LPCTSTR出错!!!下面是转来的方法,还没有验证!
判断文件夹是否存在:
1.用CreateDirectory(".\\FileManege",NULL);如果文件夹FileManege不存在,则创建。
2.或者if(_access(".\\FileManege",0)==-1),表示FileManege不存在。
3.或者BOOL PathIsDirectory(LPCTSTR pszPath);
二、判断文件是否存在:
1.用if((file=fopen(".\\FileManege\\F\\F.dat","rb"))==NULL)
file=fopen(".\\FileManege\\F\\F.dat","ab+"); // 先判断有无文件,没的话新建一个
2.用if(_access(".\\FileManege\\F\\F.dat",0)==-1),表示文件不存在。
函数int _access( const char *path, int mode );可以判断文件或者文件夹的mode属性
mode=00;//Existence only
mode=02;//Write permission
mode=04;//Read permission
mode=06;//Read and write permission
需要包含头文件<io.h>。
下面是从CSDN论坛转来的
1.C++很简单的一种办法:
[cpp] view
plaincopy
#include < iostream >
#include < fstream >
using namespace std;
#define FILENAME "stat.dat"
int main()
{
fstream _file;
_file.open(FILENAME,ios:: in );
if ( ! _file)
{
cout << FILENAME << " 没有被创建 " ;
}
else
{
cout << FILENAME << " 已经存在 " ;
}
return 0 ;
}
2.利用 c 语言的库的办法:
函数名: _access
功 能: 确定文件的访问权限
用 法: int access(const char *filename, int amode);
Determine file-access permission.
int _access( const char *path, int mode );
int _waccess( const wchar_t *path, int mode );
参考MSDN
Return Value
Each of these functions returns 0 if the file has the given mode. The function returns –1 if the named file does not exist or is not accessible in the given mode; in this case, errno is set as follows:
EACCES
Access denied: file’s permission setting does not allow specified access.
ENOENT
Filename or path not found.
Parameters
path
File or directory path
mode
Permission setting
Remarks
When used with files, the _access function determines whether the specified file exists and can be accessed as specified by the value of mode . When used with directories, _access determines
only whether the specified directory exists; in Windows NT, all directories have read and write access.
mode Value Checks File For
00 Existence only
02 Write permission
04 Read permission
06 Read and write permission
Generic-Text Routine Mappings
Example
[cpp] view
plaincopy
/* ACCESS.C: This example uses _access to check the
* file named "ACCESS.C" to see if it exists and if
* writing is allowed.
*/
#include <io.h>
#include <stdio.h>
#include <stdlib.h>
void main( void )
{
/* Check for existence */
if( (_access( "ACCESS.C", 0 )) != -1 )
{
printf( "File ACCESS.C exists/n" );
/* Check for write permission */
if( (_access( "ACCESS.C", 2 )) != -1 )
printf( "File ACCESS.C has write permission/n" );
}
}
Output
3.在windows平台下用API函数FindFirstFile(...):
(1)检查文件是否存在:
[cpp] view
plaincopy
#define _WIN32_WINNT 0x0400
#include <windows.h>
int main( int argc, char * argv[])
{
WIN32_FIND_DATA FindFileData;
HANDLE hFind;
printf ( " Target file is %s. " , argv[ 1 ]);
hFind = FindFirstFile(argv[ 1 ], & FindFileData);
if (hFind == INVALID_HANDLE_VALUE) {
printf ( " Invalid File Handle. Get Last Error reports %d " , GetLastError ());
} else {
printf ( " The first file found is %s " , FindFileData.cFileName);
FindClose(hFind);
}
return ( 0 );
}
(2)检查某一目录是否存在:
[cpp] view
plaincopy
/// 目录是否存在的检查:
bool CheckFolderExist( const string & strPath)
{
WIN32_FIND_DATA wfd;
bool rValue = false ;
HANDLE hFind = FindFirstFile(strPath.c_str(), & wfd);
if ((hFind != INVALID_HANDLE_VALUE) && (wfd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY))
{
rValue = true ;
}
FindClose(hFind);
return rValue;
}
4.使用boost的filesystem类库的exists函数
[cpp] view
plaincopy
#include < boost / filesystem / operations.hpp >
#include < boost / filesystem / path.hpp >
#include < boost / filesystem / convenience.hpp >
int GetFilePath(std:: string & strFilePath)
{
string strPath;
int nRes = 0 ;
// 指定路径
strPath = " D:/myTest/Test1/Test2 " ;
namespace fs = boost::filesystem;
// 路径的可移植
fs::path full_path( fs::initial_path() );
full_path = fs::system_complete( fs::path(strPath, fs::native ) );
// 判断各级子目录是否存在,不存在则需要创建
if ( ! fs::exists( full_path ) )
{
// 创建多层子目录
bool bRet = fs::create_directories(full_path);
if ( false == bRet)
{
return - 1 ;
}
}
strFilePath = full_path.native_directory_string();
return 0 ;
}
在使用PathFileExists输入参数LPCTSTR出错!!!下面是转来的方法,还没有验证!
判断文件夹是否存在:
1.用CreateDirectory(".\\FileManege",NULL);如果文件夹FileManege不存在,则创建。
2.或者if(_access(".\\FileManege",0)==-1),表示FileManege不存在。
3.或者BOOL PathIsDirectory(LPCTSTR pszPath);
二、判断文件是否存在:
1.用if((file=fopen(".\\FileManege\\F\\F.dat","rb"))==NULL)
file=fopen(".\\FileManege\\F\\F.dat","ab+"); // 先判断有无文件,没的话新建一个
2.用if(_access(".\\FileManege\\F\\F.dat",0)==-1),表示文件不存在。
函数int _access( const char *path, int mode );可以判断文件或者文件夹的mode属性
mode=00;//Existence only
mode=02;//Write permission
mode=04;//Read permission
mode=06;//Read and write permission
需要包含头文件<io.h>。
下面是从CSDN论坛转来的
1.C++很简单的一种办法:
[cpp] view
plaincopy
#include < iostream >
#include < fstream >
using namespace std;
#define FILENAME "stat.dat"
int main()
{
fstream _file;
_file.open(FILENAME,ios:: in );
if ( ! _file)
{
cout << FILENAME << " 没有被创建 " ;
}
else
{
cout << FILENAME << " 已经存在 " ;
}
return 0 ;
}
2.利用 c 语言的库的办法:
函数名: _access
功 能: 确定文件的访问权限
用 法: int access(const char *filename, int amode);
Determine file-access permission.
int _access( const char *path, int mode );
int _waccess( const wchar_t *path, int mode );
参考MSDN
Return Value
Each of these functions returns 0 if the file has the given mode. The function returns –1 if the named file does not exist or is not accessible in the given mode; in this case, errno is set as follows:
EACCES
Access denied: file’s permission setting does not allow specified access.
ENOENT
Filename or path not found.
Parameters
path
File or directory path
mode
Permission setting
Remarks
When used with files, the _access function determines whether the specified file exists and can be accessed as specified by the value of mode . When used with directories, _access determines
only whether the specified directory exists; in Windows NT, all directories have read and write access.
mode Value Checks File For
00 Existence only
02 Write permission
04 Read permission
06 Read and write permission
Generic-Text Routine Mappings
TCHAR.H Routine | _UNICODE & _MBCS Not Defined | _MBCS Defined | _UNICODE Defined |
_taccess | _access | _access | _waccess |
[cpp] view
plaincopy
/* ACCESS.C: This example uses _access to check the
* file named "ACCESS.C" to see if it exists and if
* writing is allowed.
*/
#include <io.h>
#include <stdio.h>
#include <stdlib.h>
void main( void )
{
/* Check for existence */
if( (_access( "ACCESS.C", 0 )) != -1 )
{
printf( "File ACCESS.C exists/n" );
/* Check for write permission */
if( (_access( "ACCESS.C", 2 )) != -1 )
printf( "File ACCESS.C has write permission/n" );
}
}
Output
File ACCESS.C exists File ACCESS.C has write permission
3.在windows平台下用API函数FindFirstFile(...):
(1)检查文件是否存在:
[cpp] view
plaincopy
#define _WIN32_WINNT 0x0400
#include <windows.h>
int main( int argc, char * argv[])
{
WIN32_FIND_DATA FindFileData;
HANDLE hFind;
printf ( " Target file is %s. " , argv[ 1 ]);
hFind = FindFirstFile(argv[ 1 ], & FindFileData);
if (hFind == INVALID_HANDLE_VALUE) {
printf ( " Invalid File Handle. Get Last Error reports %d " , GetLastError ());
} else {
printf ( " The first file found is %s " , FindFileData.cFileName);
FindClose(hFind);
}
return ( 0 );
}
(2)检查某一目录是否存在:
[cpp] view
plaincopy
/// 目录是否存在的检查:
bool CheckFolderExist( const string & strPath)
{
WIN32_FIND_DATA wfd;
bool rValue = false ;
HANDLE hFind = FindFirstFile(strPath.c_str(), & wfd);
if ((hFind != INVALID_HANDLE_VALUE) && (wfd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY))
{
rValue = true ;
}
FindClose(hFind);
return rValue;
}
4.使用boost的filesystem类库的exists函数
[cpp] view
plaincopy
#include < boost / filesystem / operations.hpp >
#include < boost / filesystem / path.hpp >
#include < boost / filesystem / convenience.hpp >
int GetFilePath(std:: string & strFilePath)
{
string strPath;
int nRes = 0 ;
// 指定路径
strPath = " D:/myTest/Test1/Test2 " ;
namespace fs = boost::filesystem;
// 路径的可移植
fs::path full_path( fs::initial_path() );
full_path = fs::system_complete( fs::path(strPath, fs::native ) );
// 判断各级子目录是否存在,不存在则需要创建
if ( ! fs::exists( full_path ) )
{
// 创建多层子目录
bool bRet = fs::create_directories(full_path);
if ( false == bRet)
{
return - 1 ;
}
}
strFilePath = full_path.native_directory_string();
return 0 ;
}
相关文章推荐
- C# C++ 判断文件 文件夹是否存在
- 判断文件夹、文件是否存在、创建文件 c++ matlab
- C++用Windows API判断文件或文件夹是否存在
- C++ 判断文件文件夹是否存在
- C/C++中判断文件或文件夹是否存在
- C++遍历文件夹及判断某一文件或目录是否存在
- c++判断文件或文件夹是否存在--转载
- VC C++ 判断文件夹中是否存在某个文件
- C/C++判断文件/文件夹是否存在
- c++ 判断文件或文件夹是否存在
- C/C++判断文件/文件夹是否存在
- [C/C++相关]C语言判断文件夹或者文件是否存在的方法
- C++文件与文件夹操作(1)--判断文件和文件夹是否存在
- c++ 判断文件、文件夹(路径)是否存在
- C++ 获取文件夹内的文件名,判断文件(夹)是否存在的两个函数
- C/C++判断文件文件夹是否存在
- C/C++判断文件/文件夹是否存在 转
- 几个C#编程的小技巧 (二) (判断文件或文件夹是否存在 )
- Python判断文件和文件夹是否存在的方法
- asp.net 判断指定路径指定文件夹下是否有图片文件存在