C Library Functions - getline (3)
NAME
getline(3f) - [M_io:READ] read a line from specified LUN into allocatable string up to line length limit (LICENSE:PD)
CONTENTS
Syntax
Description
Options
Returns
Example
Author
License
SYNTAX
function getline(line,lun,iostat) result(ier)
character(len=:),allocatable,intent(out) :: line integer,intent(in),optional :: lun integer,intent(out),optional :: iostat integer :: ier
DESCRIPTION
Read a line of any length up to programming environment maximum line length. Requires Fortran 2003+.It is primarily expected to be used when reading input which will then be parsed.
The input file must have a PAD attribute of YES for the function to work properly, which is typically true.
The simple use of a loop that repeatedly re-allocates a character variable in addition to reading the input file one buffer at a time could (depending on the programming environment used) be inefficient, as it could reallocate and allocate memory used for the output string with each buffer read.
OPTIONS
LINE line read LUN optional LUN (Fortran logical I/O unit) number. Defaults to stdin. IOSTAT status returned by READ(IOSTAT=IOS). If not zero, an error occurred or an end-of-file or end-of-record was encountered. This is the same value as returned by the function. See the example program for a usage case.
RETURNS
IER zero unless an error occurred. If not zero, LINE returns the I/O error message.
EXAMPLE
Sample program:
program demo_getline use,intrinsic :: iso_fortran_env, only : stdin=>input_unit use,intrinsic :: iso_fortran_env, only : iostat_end use M_io, only : getline implicit none integer :: iostat character(len=:),allocatable :: line open(unit=stdin,pad=’yes’) INFINITE: do while (getline(line,iostat=iostat)==0) write(*,’(a)’)’[’//line//’]’ enddo INFINITE if(iostat /= iostat_end)then write(*,*)’error reading input:’,trim(line) endif end program demo_getline
AUTHOR
John S. Urban
LICENSE
Public Domain
| Nemo Release 3.1 | getline (3) | July 22, 2023 |
