Check if file existing or not in c

Question

prgchDirPath is char pointer. But expected is LPCWSTR. How to change this?

prgchDirPath is a directory path. File is not existed. But I want to make sure if directory/path exists or not. Can the API below helps me? if yes, how?

unsigned char IsFilePathCorrect(char* prgchDirPath)
{
        WIN32_FIND_DATA FindFileData;
        HANDLE handle;
        int found=0;

        //1. prgchDirPath is char pointer. But expected is LPCWSTR.
        //How to change this?
        //2. prgchDirPath is a directory path. File is not existed.
        //But I want to make sure if directory/path exists or not.
        //Can the API below helps me? if yes, how?
        handle = FindFirstFile(prgchDirPath, &FindFileData);
        if(handle != INVALID_HANDLE_VALUE)
        found = 1;
        if(found) 
        {
            FindClose(handle);
        }
        return found;
}

I want to check if directory path is existed or not. Please provide one sample code. Thank you.

Try calling the narrow version of FindFirstFile, `FindFirstFileA`, and use the narrow version of the structure, `WIN32_FIND_DATAA` — WhozCraig, Sep 15 '13 at 06:39
@WhozCraig Thanks allot. I could pass char pointer directly now. But problem is, I passed "C:\\" and '&FindFileData' to this API and it gave return code 0xFFFFFFFF, that means not found right? The path C:\ existed in my local drive. — SHRI, Sep 15 '13 at 06:47
It means not found because that isn't the *directory*, its just a path to one. You're not finished yet. Try `"C:\\."` — WhozCraig, Sep 15 '13 at 06:49
@WhozCraig You are right, I created a directory called 'xx' and gave path as `"C:\\xx"` and it worked. But I also tried giving `"C:\\."`, but it did not work. — SHRI, Sep 15 '13 at 07:12
If you want to check if a drive letter exists you can use `GetLogicalDrives`. — Jonathan Potter, Sep 15 '13 at 11:48
The answer is in a different question: [C++ `PathFileExists` limited to 260 chars](http://stackoverflow.com/questions/13877994/c-pathfileexists-limited-to-260-chars). — IInspectable, Sep 15 '13 at 11:59

score 2 · Answer 1 · answered Sep 15 '13 at 07:03

2

You can simply use access, which is widely supported on Windows, Linux, Mac, etc: access(filepath, 0) returns 0 if file exists, and error code otherwise. On Windows, you will need to #include <io.h>.

answered Sep 15 '13 at 07:03

mvp

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Rahul Tripathi · Answer 2 · 2013-09-15T06:50:37.437

How about doing it like this using getAttributes function:-

BOOL DirectoryExists(LPCTSTR szPath)
{
  DWORD dwAttrib = GetFileAttributes(szPath);

  return (dwAttrib != INVALID_FILE_ATTRIBUTES && 
         (dwAttrib & FILE_ATTRIBUTE_DIRECTORY));
}

or you can try this too:-

#include <io.h>     // For access().
#include <sys/types.h>  // For stat().
#include <sys/stat.h>   // For stat().

bool DirectoryExists( const char* path){

    if( _access( path, 0 ) == 0 ){

        struct stat s;
        stat( path, &s);

        return (s.st_mode & S_IFDIR) != 0;
    }
    return false;
}

Vivek S · Answer 3 · 2013-09-15T07:07:54.027

0

You can check whether the path is correct or not without using any Windows API as shown below

    /*
     * Assuming that prgchDirPath is path to a directory
     * and not to any file.
     */
    unsigned char IsFilePathCorrect(char* prgchDirPath)
    {
        FILE *fp;
        char path[MAX_PATH] = {0};

        strcpy(path, prgchDirPath);
        strcat(path, "/test.txt");

        fp = fopen(path, "w");
        if (fp == NULL)
            return 0;

        fclose(fp);
        return 1;
    }

edited Sep 15 '13 at 07:07

answered Sep 15 '13 at 06:49

Vivek S

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And if the directory path is valid but the file `"test.txt"` isn't there? – WhozCraig Sep 15 '13 at 06:59
@WhozCraig - You are right, the second argument should be "w" instead of "r". Thanks for pointing it out. – Vivek S Sep 15 '13 at 07:07
Even changing it to `"w"` isn't going to work if you don't have write-permission on the folder. You need a non-intrusive method. – WhozCraig Sep 15 '13 at 08:01

score 0 · Answer 4 · answered Sep 16 '13 at 07:36

#include<stdio.h>
#include<fcntl.h>

#define DEVICE "test.txt"

int main()
{
    int value = 0;
    if(access(DEVICE, F_OK) == -1) {
        printf("file %s not present\n",DEVICE);
        return 0;
    }
    else
        printf("file %s present, will be used\n",DEVICE);
    return 0;
}

Check if file existing or not in c

4 Answers4