A close system call is a
system call used to close a
file descriptor by the
kernel. For most
file systems, a
program
Program, programme, programmer, or programming may refer to:
Business and management
* Program management, the process of managing several related projects
* Time management
* Program, a part of planning
Arts and entertainment Audio
* Programm ...
terminates access to a
file in a filesystem using the close system call. This flushes file buffers, updates file
metadata, which may include and
end-of-file indicator in the data; de-allocates resources associated with the file (including the
file descriptor) and updates the system wide table of files in use. Some
programming languages maintain a
data structure
In computer science, a data structure is a data organization, management, and storage format that is usually chosen for efficient access to data. More precisely, a data structure is a collection of data values, the relationships among them, ...
of files opened by their
runtime library
In computer programming, a runtime library is a set of low-level routines used by a compiler to invoke some of the behaviors of a runtime environment, by inserting calls to the runtime library into compiled executable binary. The runtime enviro ...
and may close when the program terminates. This practice is known as
resource acquisition is initialization (RAII). Some operating systems will invoke the
close on files held by a program if it terminates. Some operating systems will invoke the
close syscall as part of an operating system recovery as a result of a system failure.
C library POSIX definition
The
closecall is standardized by the
POSIX
The Portable Operating System Interface (POSIX) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines both the system- and user-level application programming in ...
specification
int close (int filedes);
int fclose (FILE *stream);
The function returns zero to indicate the file was closed successfully. If any error occurs, a value of -1 is returned and errno is appropriately set.
The errors that can occur include:
;
: The argument supplied was not a valid file descriptor
;
: The function call was interrupted by a
signal
;
: An
I/O error occurred
References
POSIX close
External links
*
{{Computer files
C POSIX library
System calls