How can i create a temporary folder in tmp folder using C++ language.
I have 3 volumes. Leopard, Development and 10.6 (in Mac OS X) and I want to create a temp directory in current home directory.
Here is my code. I am confused about this line char* tempdir = "/Volumes/Development/NewFolder.XXXXXX":
if (!mkdtemp(tempdir))
fprintf(stderr, "Not able to create directory");
Under POSIX, you can use mkdtemp to create a directory with a unique name. On Windows, use GetTempPath to retrieve the name of the temp directory, then create a directory with a random name there.
You can use the boost::Filesystem library function: create_directory( "temp" );
This is very portable and will work under most operating systems.
Boost can be downloaded here.
Boost is an excellent choice, but one of the problems with boost is that you would probably be downloading a huge amount of sources - if all you need is the filesystem functionality this is a bit of an overkill. Try http://stlplus.sourceforge.net/stlplus3/docs/file_system.html
Also why don't you just use the good old system() function? The string argument to system of course would be platform dependent.
Arpan
Related
I'm trying to understand how I can create a ".config" file containing a bunch of parameters to later use to set up the variables in my C project on Unix.
I created my ".config" file using sudo nano test.config and wrote some stuff inside such as:
#N is this
N 10
#p is that
p 0.002
#T is this
T 10
Now that I did that how can I read its content and use it to initialize my variables?
The several answers to this question explain how to parse that config file, but you could use standard parsing techniques (perhaps your own recursive descent parser) or Glib's lexical scanning or key-value pair parser (or use something else). You certainly should define and document (perhaps using EBNF) what is the format of that textual configuration file (and what the various entries there represent: for example, if that configuration file refers to other files, how do you handle spaces in such file paths, etc....). A common (but not universal) convention is to consider as comments so skip any line starting with #.
Another question is how to get that config file while running in an arbitrary working directory. You just need to build the absolute path of your file (for fopen(3) or open(2)), e.g. with
char configpath[100];
snprintf(configpath, sizeof(configpath), "%s/.test.config", getenv("HOME"));
You could test before that getenv("HOME") is not NULL, but in practice that is very unlikely; see environ(7) and getenv(3); and the case when it gives a very long file path is also unlikely; you might test that snprintf(3) returns a count less than sizeof(configpath) or use asprintf(3).
You might use other functions, e.g. glob(3) or wordexp(3) to get that file path (but you probably should stick to snprintf or asprintf with getenv("HOME")...).
You might consider instead embedding some scriptable interpreter like lua or guile in your program (but that is a strong architectural design decision). Then the configuration file becomes some (Turing-complete!) script.
BTW, there is no need to use sudo to edit that configuration file (under your home directory), and you might decide to also read some system-wide configuration under /etc/
I wants to get the names of execute files in some directory in Linux.
How can I do it?
I tried to use opendir like this:
dir = opendir(directoryName);
I need to get only the names of the execute files.
I programming in C.
thanks :)
You should define what you mean by executable files.
That could be any file with its execute bit (it is the owner, group, or other) set. Then test with access(2) & X_OK and/or use stat(2).
That could also be only ELF executables. See elf(5); then the issue might be to check that a file could indeed be executed, which might be difficult (what about missing library dependencies? or ill-formed ELF files?). Maybe use libelf (and/or libmagic to do the equivalent of file(1) command).
To scan recursively a file tree, use nftw(3); to scan just a directory use opendir(3) & readdir(3) (don't forget the closedir!), then you'll probably need to build the complete file path from each directory entry (perhaps using snprintf(3) or asprintf(3))
See also Advanced Linux Programming
I'm trying to remove a file in a C program, but when I use the remove() function it completely removes the file and not sending it to the trash. How can I remove a file to trash?
Thanks in advance!
On Mac OS, you should use the recycleURLs:completionHandler: method in NSWorkspace.
Almost every operating system provides an API to perform a soft delete by moving files to the trash. Unfortunately there is no unified specification on how a trash / recycling bin should work. On Windows you can use IFileOperation, macOS has the NSFileManager and on Linux and BSD you either use a tool that implements the FreeDesktop.org trash specification such as gio trash (GNOME), kioclient5 move (KDE), trash-cli or implement your own.
Another solution is using a cross-platform library that allows to move files and directories to the trash / recycling bin like libtrashcan. This simplifies development because you only use a single function call without worrying about platform specific details.
For Windows See SHFileOperation with FOF_ALLOWUNDO.
http://msdn.microsoft.com/en-us/library/bb762164.aspx
On Mac OS X, you have to call FSMoveObjectToTrashSync (or its async friend) from CoreServices.
In linux i will do...
system("mv your_file.txt /home/username/.local/share/Trash/");
If you are on Windows try this.
Open a Command Prompt (DOS windows) and type
cd \$RECYCLE.BIN
dir \a
and you will get a list of all the trashes of all the users in your computer.
In your program move the file to the proper trash.
Is there any function to check file(s) exist with specific extension or pattern in a directory(s) in Windows and Linux?
For example, to check for files with bbram extension in nvmdir directory.
file_exists(nvmdir .. "\\*.bbram")
A somewhat less elegant solution would be to use popen() or even lesser elegant system() to issue an OS specific "shell" command.
If you want linux/windows compatibility I guess you'll need to do it yourself (look at #ifdef etc to define witch os you're using).
Then you'll need opendir (http://man7.org/linux/man-pages/man3/opendir.3.html), readdir (http://man7.org/linux/man-pages/man3/readdir.3.html) functions.
I let you dig into it.
Compiling on the shared CentOS server is not allowed. Therefore, I compile my program in my Debian computer, linking it with Debian's system libraries such as libc, etc. Then I upload my program and the Debian system libraries and my program works. The only problem is that setlocale() does not work at CentOS. CentOS has "en_US.utf8" installed and works on all programs except mine. I suspect that I have to also upload Debian's locale files ? How could I link my program to the Debian locale files ? I tried to use LOCPATH but I am unsure of how it works exactly. Which files do I have to link to and how ?
C program:
setenv("LOCPATH", "/", 1);
if (setlocale(LC_ALL, "en_US.utf8") == NULL) {
puts("not set");
}
I used a hex editor to modify the path to /usr/lib/locale/locale-archive which apparently is the only file that setlocale() uses according to strace. This method is dirty but it worked.
According to man LOCPATH, this environment variable is non-standard, so its use is not recommended. No examples are given anywhere of how to use it nor what is meant exactly by a path to "locale's object files".
I guess the only real way of modifying the path is a glibc modification and recompilation.
Quote: LOCPATH is an environment variable that tells the setlocale() function the name of the directory from which to load locale object files. If LOCPATH is not defined, the default directory /usr/lib/nls/locale is searched. LOCPATH is similar to the PATH environment variable; it contains a list of z/OS UNIX directories separated by colons.
So just specifying / and hoping that it does a recursive search will not work.
You could also produce a static binary and upload that to the host.