I am having trouble in creating named pipe in Android and the example below illustrates my dilemma:

res = mkfifo("/sdcard/fifo9000", S_IRWXO);
if (res != 0)
{
    LOG("Error while creating a pipe (return:%d, errno:%d)", res, errno);
}

The code always prints:

Error while creating a pipe (return:-1, errno:1)

I can't figure out exactly why this fails. The application has android.permission.WRITE_EXTERNAL_STORAGE permissions. I can create normal files with exactly the same name in the same location, but pipe creation fails. The pipe in question should be accessible from multiple applications.

1. I suspect that noone can create pipes in /sdcard. Where would it be the best location to do so?
2. What mode mast should I set (2nd parameter)?
3. Does application need any extra permissions?