Standard I/O library - Revision history

Jnc: typo

2025-09-21T13:43:16Z

typo

Jnc: grammar typo

2023-01-01T09:22:32Z

grammar typo

Jnc: add detail on fundamentals

2022-12-31T23:05:53Z

add detail on fundamentals

Jnc: Covers the basics

2022-12-31T21:53:16Z

Covers the basics

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The '''Standard I/O library''' is now the canonical [[buffer]]ed [[input/output]] [[subroutine package]] for the [[C programming language]] (which does not include any I/O as part of the [[programming language]] itself). It was a replacement for the earlier Portable C Library, which had basically the same functionality, but was structured slightly differently.

Its purpose is prinipally to allow [[application]]s to process one [[byte]] at a time efficiently. Although many [[operating system]]s allow a [[file]] to be read a byte at a time, the overhead of doing a whole [[system call]] for each byte will make the processing of the file a lot slower than using this library. Using this library also allows applications to be [[portable]] by hiding the details of the operating system calls to be hidden.

Some things in it:

* getchar()
* getc()
* putchar()
* putc()
* feof()
* ferror()
* fileno()

look like [[subroutine]] calls, but are actually in-line [[macro]]s.

It also includes a number of other capabilities, such as producing numeric output, and structured output.

==External links==

* [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V6/usr/doc/iolib/iolib The Portable C Library]
* [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V7/usr/man/man3/stdio.3s stdio - standard buffered input/output package] - overview man page
* [https://www.tuhs.org/cgi-bin/utree.pl?file=32V/usr/doc/ctour/ios.r A New Input-Output Package] - full write-up by Dennis M. Ritchie

[[Category: C Language]]

← Older revision		Revision as of 13:43, 21 September 2025
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−	The '''Standard I/O library''' is now the canonical [[buffer]]ed [[input/output]] [[subroutine package]] for the [[C programming language]] (which does not include any I/O as part of the [[programming language]] itself). Its purpose is ~~prinipally~~ to allow [[application]]s to process one [[byte]] at a time efficiently. Although many [[operating system]]s allow a [[file]] to be read a byte at a time, the overhead of doing a whole [[system call]] for each byte will make the processing of the file a lot slower than using this library. Using this library also allows applications to be [[portable]], by hiding the details of the operating system calls to be used.	+	The '''Standard I/O library''' is now the canonical [[buffer]]ed [[input/output]] [[subroutine package]] for the [[C programming language]] (which does not include any I/O as part of the [[programming language]] itself). Its purpose is principally to allow [[application]]s to process one [[byte]] at a time efficiently. Although many [[operating system]]s allow a [[file]] to be read a byte at a time, the overhead of doing a whole [[system call]] for each byte will make the processing of the file a lot slower than using this library. Using this library also allows applications to be [[portable]], by hiding the details of the operating system calls to be used.

	Some operations in it:		Some operations in it:

@@ Line 1: / Line 1: @@
-The '''Standard I/O library''' is now the canonical [[buffer]]ed [[input/output]] [[subroutine package]] for the [[C programming language]] (which does not include any I/O as part of the [[programming language]] itself). Its purpose is prinipally to allow [[application]]s to process one [[byte]] at a time efficiently. Although many [[operating system]]s allow a [[file]] to be read a byte at a time, the overhead of doing a whole [[system call]] for each byte will make the processing of the file a lot slower than using this library. Using this library also allows applications to be [[portable]] by hiding the details of the operating system calls to be hidden.
+The '''Standard I/O library''' is now the canonical [[buffer]]ed [[input/output]] [[subroutine package]] for the [[C programming language]] (which does not include any I/O as part of the [[programming language]] itself). Its purpose is prinipally to allow [[application]]s to process one [[byte]] at a time efficiently. Although many [[operating system]]s allow a [[file]] to be read a byte at a time, the overhead of doing a whole [[system call]] for each byte will make the processing of the file a lot slower than using this library. Using this library also allows applications to be [[portable]], by hiding the details of the operating system calls to be used.
-Some things in it:
+Some operations in it:
 * getchar()
@@ Line 13: / Line 13: @@
 look like [[subroutine]] calls, but are actually in-line [[macro]]s.
-It also includes a number of other capabilities, such as producing numeric output, and structured output.
+It also includes a number of other capabilities, such as producing numeric output, structured output, etc.
 It was a replacement for the earlier Portable C Library, which had basically the same functionality, but was structured slightly differently. In the Portable library, open files were identified by small integers; the standard library uses [[pointer]]s to [[structure]]s which hold all the data related to a particular file.