In C, how can I create a file from a filepath, even if the directories are not existing?

I am taking a file path from a user. I need to then access that file, and create it if it does not exist. I also need to create any intermediate directories if they don't exist as well.

For example, if my directory looks like:

mydir
|
+---subdir
|   |
|   +-- FileA
|
+---File1

I might receive mydir/subd开发者_如何学JAVAir/FileA and would then access the relevant file. However, I might also receive mydir/NewDir/FileB.

How can I do this using Unix system calls in C? I have tried using open() with the (O_RDWR | O_CREAT) flags, but this didn't work out.

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I think this answer covers your question:

Recursive mkdir() system call on Unix

In short, you must create the subdirs yourself.

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If you are allowed to use it, OS calls can be wrapped inside system() call. e.g. for listing files system( "ls" );

To create a directory including the intermediate ones, use mkdir with -p

mkdir -p mydir/NewDir/

(AFAIK, it doesn't hurt if NewDir already existed.)

To create an empty file, use touch

touch mydir/NewDir/FileB

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Followup: I wrote this quick proof-of-concept program and tested in cygwin.

#include <stdlib.h>
#include <string.h>

int main() {

    char const * dir = "dir/subdir";
    char const * file = "file";

    char mkdirCmd[ 80 ] = { 0 };
    strcat( mkdirCmd, "mkdir -p " );
    strcat( mkdirCmd, dir );

    char touchCmd[ 80 ] = { 0 };
    strcat( touchCmd, "touch " );
    strcat( touchCmd, dir );
    strcat( touchCmd, "/" );
    strcat( touchCmd, file );

    system( mkdirCmd );
    system( touchCmd );

    return 0;
}

Unit test:

$ ls
mkdir.c  mkdir.exe*

$ ./mkdir.exe 

$ ls
dir/  mkdir.c  mkdir.exe*

$ ls -R dir
dir:
subdir/

dir/subdir:
file

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Unfortunately there is no recursive 'makedir' so I'm scared that you might have to do it yourself.

But I think its gonna be easy doing it

function recursiveCreate(filepath) split the filepath by slash if last part create file else create directory end

Now you have your function :) using it will make you happier than using some UNIX defined function :)