C File Error
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handling but being a system programming language, it provides you access at lower level in the form of return values. Most of the C or even Unix function calls return -1 or NULL in case of any error and set an error code errno. It is set as a global variable and indicates an error occurred during any function call. You can find various error codes defined in
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more about Stack Overflow the company Business Learn more about hiring developers or ferror posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow c open Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up How to catch error in FILE IO using C? https://www.tutorialspoint.com/cprogramming/c_error_handling.htm up vote 1 down vote favorite I am using following code snippet in C to copy a file: #define CHUNK 4096 char buf[CHUNK]; FILE *file , *out; size_t nread; file = fopen("test", "rb"); out = fopen("out", "wb"); if (file) { while ((nread = fread(buf, 1, sizeof buf, file)) > 0) fwrite(buf, 1, nread, out); if (ferror(file)) { /* Not getting error here */ } fclose(file); fclose(out); } My http://stackoverflow.com/questions/9325962/how-to-catch-error-in-file-io-using-c file is very large (200 MB), I have to handle errors if file is moved or removed while reading, writing is in progress. How can I do that? Let me clear it tad more, Any how I will get access to path by some wifi means. So if wifi will be disconnected then how I'll get the error.. c io large-files share|improve this question edited Feb 17 '12 at 12:46 asked Feb 17 '12 at 9:43 Yuvi 81111535 shouldn't the OS layer take of this? as long as a process exist and uses file access, the os internally keeps track of it, although if it gets e.g. moved? I think linux does that. –Bort Feb 17 '12 at 9:55 You're using Windows, right? Could you use one of the "sharing" file operations? Check out, for instance, _sopen_s. –Mr Lister Feb 17 '12 at 9:58 I am using linux platform, While the process is going on I delete file using this sudo rm -f test now there is no even lock file, but still getting proper output. –Yuvi Feb 17 '12 at 10:57 because the real deletion of the file happens when the la
codes can’t occur on GNU systems, but they can occur using the GNU C Library on other systems. Macro: int EPERM Operation not permitted; only the owner of the http://www.gnu.org/s/libc/manual/html_node/Error-Codes.html file (or other resource) or processes with special privileges can perform the operation. Macro: int ENOENT No such file or directory. This is a “file doesn’t exist” error for ordinary files that are http://man7.org/linux/man-pages/man3/errno.3.html referenced in contexts where they are expected to already exist. Macro: int ESRCH No process matches the specified process ID. Macro: int EINTR Interrupted function call; an asynchronous signal occurred and prevented completion error codes of the call. When this happens, you should try the call again. You can choose to have functions resume after a signal that is handled, rather than failing with EINTR; see Interrupted Primitives. Macro: int EIO Input/output error; usually used for physical read or write errors. Macro: int ENXIO No such device or address. The system tried to use the device represented by a file you specified, c file error and it couldn’t find the device. This can mean that the device file was installed incorrectly, or that the physical device is missing or not correctly attached to the computer. Macro: int E2BIG Argument list too long; used when the arguments passed to a new program being executed with one of the exec functions (see Executing a File) occupy too much memory space. This condition never arises on GNU/Hurd systems. Macro: int ENOEXEC Invalid executable file format. This condition is detected by the exec functions; see Executing a File. Macro: int EBADF Bad file descriptor; for example, I/O on a descriptor that has been closed or reading from a descriptor open only for writing (or vice versa). Macro: int ECHILD There are no child processes. This error happens on operations that are supposed to manipulate child processes, when there aren’t any processes to manipulate. Macro: int EDEADLK Deadlock avoided; allocating a system resource would have resulted in a deadlock situation. The system does not guarantee that it will notice all such situations. This error means you got lucky and the system noticed; it might just hang. See File Locks, for an example. Macro: int ENOMEM No memory
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