I'm trying to check if a folder has any subfolders without iterating through its children, in Linux. The closest I've found so far is using ftw and stopping at the first subfolder - or using scandir and filtering through the results. Both, are, however, an overkill for my purposes, I simply want a yes/no. On Windows, this is done by cal...
If I fork a child process, and the child process exits before the parent calls waitpid, then is the exit status information that is set by waitpid still valid? If so, when does it become not valid; i.e., how do I ensure that I can call waitpid on the child pid and continue to get valid exit status information after an arbitrary amount o...
I have a file descriptor that is open for reading which may be non-blocking. What I need to do is simply read all data until reaching EOF and write that data to a writable file descriptor. As the process that performs this copying is not "aware" of anything that is going on around it, I don't think that I can do something useful while wa...
Is the O_LARGEFILE flag needed if all that I want to do is write a large file (O_WRONLY) or append to a large file (O_APPEND | O_WRONLY)? From a thread that I read titled "Cannot write >2gb index file" on the CLucene-dev mailing list, it appears that O_LARGEFILE might be needed to write large files, but participants in that discussion a...
From what I have been reading on The Open Group website on fcntl, open, read, and write, I get the impression that whether O_NONBLOCK is set on a file descriptor, and hence whether non-blocking I/O is used with the descriptor, should be a property of that file descriptor rather than the underlying file. Being a property of the file descr...
I would like to safely be able to simulate open with O_CREAT | O_WRONLY | O_TRUNC | O_NOFOLLOW and O_CREAT | O_WRONLY | O_APPEND | O_NOFOLLOW on systems that do not support O_NOFOLLOW. I can somewhat achieve what I am asking for with: struct stat lst; if (lstat(filename, &lst) != -1 && S_ISLNK(lst.st_mode)) { errno = ELOOP; retu...
Hello, consider the following task : 1) read a target directory contents, pass each found dirent structure to some filter function and remember filtered elements somehow for the later processing 2) some time later, iterate through the filtered elements and process them (do some I/O) The most obvious way is to save names of sub-direc...