Editing Fortran (section)

===Transition to ANSI Standard Fortran===
The development of a revised standard to succeed FORTRAN 77 would be repeatedly delayed as the standardization process struggled to keep up with rapid changes in computing and programming practice.  In the meantime, as the "Standard FORTRAN" for nearly fifteen years, FORTRAN 77 would become the historically most important dialect.

An important practical extension to FORTRAN 77 was the release of MIL-STD-1753 in 1978.<ref>{{cite book
  | title = MIL-STD 1753 - FORTRAN, DoD Supplement To American National Standard X3.9-1978
|date=November 9, 1978
  | publisher = [[United States Government Printing Office]]
  | url = https://wg5-fortran.org/ARCHIVE/mil_std_1753.html
  | access-date = April 21, 2024
  }}</ref> This specification, developed by the [[United States Department of Defense|U.S. Department of Defense]], standardized a number of features implemented by most FORTRAN 77 compilers but not included in the ANSI FORTRAN 77 standard. These features would eventually be incorporated into the Fortran 90 standard.

* {{code|DO WHILE}} and {{code|END DO}} statements
* {{code|INCLUDE}} statement
* {{code|IMPLICIT NONE}} variant of the {{code|IMPLICIT}} statement
* [[Bit manipulation]] intrinsic functions, based on similar functions included in [[Industrial Real-Time Fortran|Industrial Real-Time Fortran (ANSI/ISA S61.1 (1976))]]

The [[Institute of Electrical and Electronics Engineers|IEEE]] 1003.9 [[POSIX]] Standard, released in 1991, provided a simple means for FORTRAN 77 programmers to issue POSIX system calls.<ref>{{cite book
 |title        = IEEE 1003.9-1992 – IEEE Standard for InformationTechnology – POSIX(R) FORTRAN 77 Language Interfaces – Part 1: Binding for System Application Program Interface (API)
 |url          = https://standards.ieee.org/ieee/1003.9/1440/
 |publisher    = [[IEEE]]
 |access-date  = November 24, 2018
}}</ref> Over 100 calls were defined in the document{{snd}} allowing access to POSIX-compatible process control, signal handling, file system control, device control, procedure pointing, and stream I/O in a portable manner.