Resolution
- On the Tools menu, click Options.
- Click the Player tab, click to select the Download codecs automatically check box, and then click OK.
- Try to play the file. If you are prompted to install the codec, click Install.
9 Answers. A file descriptor is a low-level integer "handle" used to identify an opened file (or socket, or whatever) at the kernel level, in Linux and other Unix-like systems. A FILE pointer is a C standard library-level construct, used to represent a file.
5 Answers. Both 0 and 1 are valid return vales, and might indeed be returned if the application has closed its standard input or output file descriptors. 0 or 1 will precisely come if you have closed the stdin or stdout descriptors.
Linux systems limit the number of file descriptors that any one process may open to 1024 per process. (This condition is not a problem on Solaris machines, x86, x64, or SPARC). After the directory server has exceeded the file descriptor limit of 1024 per process, any new process and worker threads will be blocked.
File Descriptor Requirements (Linux Systems) By default, the directory server allows an unlimited number of connections but is restricted by the file descriptor limit on the operating system. Linux systems limit the number of file descriptors that any one process may open to 1024 per process.
To change the number of file descriptors in Linux, do the following as the root user:
- Edit the following line in the /etc/sysctl.conf file: fs.file-max = value. value is the new file descriptor limit that you want to set.
- Apply the change by running the following command: # /sbin/sysctl -p. Note:
At the file descriptor level, stdin is defined to be file descriptor 0, stdout is defined to be file descriptor 1; and stderr is defined to be file descriptor 2.
Stdin, stdout, and stderr
| Name | File descriptor | Abbreviation |
|---|
| Standard input | 0 | stdin |
| Standard output | 1 | stdout |
| Standard error | 2 | stderr |
On Linux, the set of file descriptors open in a process can be accessed under the path /proc/PID/fd/ , where PID is the process identifier. In Unix-like systems, file descriptors can refer to any Unix file type named in a file system.
When execvp() is executed, the program file given by the first argument will be loaded into the caller's address space and over-write the program there. execvp() returns a negative value if the execution fails (e.g., the request file does not exist).
close(2) - Linux man page
- Name. close - close a file descriptor.
- Synopsis. #include <unistd.h> int close(int fd);
- Description. close() closes a file descriptor, so that it no longer refers to any file and may be reused.
- Return Value. close() returns zero on success.
- Errors. EBADF.
- Conforming to.
- Notes.
- See Also.
The dup2() system function is used to create a copy of an existing file descriptor. In Linux, there are 3 standard file descriptors. They are: stdin: This is the standard input file descriptor.
The open function creates and returns a new file descriptor for the file named by filename . Initially, the file position indicator for the file is at the beginning of the file. The argument mode (see Permission Bits) is used only when a file is created, but it doesn't hurt to supply the argument in any case.
exec family of functions in C. The exec family of functions replaces the current running process with a new process. It can be used to run a C program by using another C program. It comes under the header file unistd.
The dup2() system function is used to create a copy of an existing file descriptor. In Linux, there are 3 standard file descriptors. stdin: This is the standard input file descriptor. It is used to take input from the terminal by default. scanf(), getc() etc functions uses stdin file descriptor to take user inputs.
It creates an open file description that refers to a file and a file descriptor that refers to that open file description. The file descriptor is used by other I/O functions to refer to that file. Applications must specify exactly one of the first three values (file access modes) below in the value of oflag: O_RDONLY.
dup2 is a system call similar to dup in that it duplicates one file descriptor, making them aliases, and then deleting the old file descriptor.
dup() and dup2() create a copy of the file descriptor oldfd. The close-on-exec flag (FD_CLOEXEC; see fcntl(2)) for the duplicate descriptor is off. dup() uses the lowest-numbered unused descriptor for the new descriptor. dup2() makes newfd be the copy of oldfd, closing newfd first if necessary.
