VC++ USES the _access function to determine whether a file or folder exists

_access function

int _access( 
 const char *path, 
 int mode 
);
int _waccess( 
 const wchar_t *path, 
 int mode 
);

Parameter

path
File or directory path.

mode
Read/write feature.

The return value
 
Each function returns 0 if the file contains a specific pattern. If the function returns -1, the name file does not exist or has a specific pattern. In this case, the Settings are shown in table errno below.

EACCES

Access denied: the file permissions Settings do not allow the specified access permissions.

ENOENT

Filename or path not found.

EINVAL

Invalid parameter.

Note

When using a file, the _access function determines whether the specified file or directory exists and has the property mode with the specified value. In use with directory, _access determines whether the specified directory exists; Only on Windows 2000 and later operating systems do all directories have read and write permissions.

mode 值	检查文件。
00	仅存在
02	Write-only
04	只读
06	读取和写入

Finally, I will give you a brief summary of VC++ to determine the existence of the file folder

Recommended example :

if(::GetFileAttributes(m_filename)==-1){// file does not exist}else{// file does exist}

1. Use the _access function, whose prototype is int _access(const char *path, int mode);

2. Using CreateFile function, the function prototype is: HANDLE CreateFile(LPCTSTR lpFileName, // pointer to name of file dwDesiredAccess, // access (read-write) mode DWORD dwShareMode, // share mode LPSECURITY_ATTRIBUTES lpSecurityAttributes, // pointer to security attributes DWORD dwCreationDisposition, // how to create dwFlagsAndAttributes, // file attributes HANDLE hTemplateFile // handle to file with attributes to // copy);

3. Use FindFirstFile function, the function prototype is: HANDLE FindFirstFile(LPCTSTR lpFileName, // pointer to name name FindFirstFile to LPWIN32_FIND_lpFindFileData pointer to information);

4. Using the GetFileAttributes function, the function prototype is as follows: DWORD GetFileAttributes(LPCTSTR lpFileName // pointer to the name of file or directory);

5. Shell Lightweight Utility APIs function PathFileExists () is used to determine whether files and directories exist or not. The file name of the function is more readable