Posix System Commands

  1. read(): The read() command returnsĀ  the number of __?___ read.
    bytes.
  2. read(): What does the read() system call do?
    In modern POSIX compliant operating systems, a program that needs to access data from a file stored in a file system uses this system call.
  3. read(): The file is identified by a file ___?___.
    descriptor
  4. read():The file is identified by a file descriptor that is normally obtained from a previous call to __?__.
    open
  5. read(): The read system call takes three arguments:
    • The file descriptor of the file.
    • The buffer where the read data is to be stored
    • The number of bytes to be read from the file.
  6. read(): file descriptor (def'n)
    An abstract indicator (handle) used to access a file or other input/output resource, such as a pipe or network socket.
  7. open(): open system call (def')
    For most file systems, a program initializes access to a file in a file system using this system call. This allocates resources associated to the file (the file descriptor), and returns a handle that the process will use to refer to that file. In some cases thisĀ  system call is performed by the first access.
  8. open(): open system call arguments (3):
    • The pathname to the file
    • The kind of access requested on the file (read, write, append etc.)
    • The initial file permission is requested using the third argument called mode. This argument is relevant only when a new file is being created.
  9. open(): path argument (describe).
    The name of the file to open. It includes the file path defining where, in which file system, the file is found (or should be created).
  10. open(): oflag argument (describe).
    This argument formed by OR'ing together optional parameters and (from <fcntl.h>) one of the following: O_RDONLY, O_RDWR and O_WRONLY
Author
geschw66
ID
329681
Card Set
Posix System Commands
Description
Fun facts and/or important rules for the POSIX system calls in linux/unix/ios.
Updated