NAG Library Routine Document

x04bbf  (line_read)

 Contents

    1  Purpose
    7  Accuracy

1
Purpose

x04bbf reads a single formatted record from an external file.

2
Specification

Fortran Interface
Subroutine x04bbf ( nin, recin, ifail)
Integer, Intent (In):: nin
Integer, Intent (Inout):: ifail
Character (*), Intent (Out):: recin
C Header Interface
#include nagmk26.h
void  x04bbf_ ( const Integer *nin, char *recin, Integer *ifail, const Charlen length_recin)

3
Description

x04bbf is used by NAG Library routines to read formatted records from an external file. All formatted input from an external file by NAG Library routines is performed by calls to x04bbf.

4
References

None.

5
Arguments

1:     nin – IntegerInput
On entry: the Fortran unit number which identifies the file to be read from. If nin<0 (not a valid Fortran unit number), then no input occurs.
2:     recin – Character(*)Output
On exit: the first lenrecin characters of the record read from unit nin, padded with trailing blanks if the record was shorter than lenrecin.
3:     ifail – IntegerInput/Output
On entry: ifail must be set to 0, -1​ or ​1. If you are unfamiliar with this argument you should refer to Section 3.4 in How to Use the NAG Library and its Documentation for details.
For environments where it might be inappropriate to halt program execution when an error is detected, the value -1​ or ​1 is recommended. If the output of error messages is undesirable, then the value 1 is recommended. Otherwise, if you are not familiar with this argument, the recommended value is 0. When the value -1​ or ​1 is used it is essential to test the value of ifail on exit.
On exit: ifail=0 unless the routine detects an error or a warning has been flagged (see Section 6).

6
Error Indicators and Warnings

If on entry ifail=0 or -1, explanatory error messages are output on the current error message unit (as defined by x04aaf).
Errors or warnings detected by the routine:
ifail=1
An end-of-file was detected by the READ statement.
System-dependent errors may also occur if the unit specified by nin is not connected to an external file, or if a read error occurs.
ifail=-99
An unexpected error has been triggered by this routine. Please contact NAG.
See Section 3.9 in How to Use the NAG Library and its Documentation for further information.
ifail=-399
Your licence key may have expired or may not have been installed correctly.
See Section 3.8 in How to Use the NAG Library and its Documentation for further information.
ifail=-999
Dynamic memory allocation failed.
See Section 3.7 in How to Use the NAG Library and its Documentation for further information.

7
Accuracy

Not applicable.

8
Parallelism and Performance

x04bbf is not threaded in any implementation.

9
Further Comments

None.

10
Example

This example program simply illustrates how a formatted record is read from the NAG Library, by first reading it into the character-string recin, used as an internal file, by x04bbf and then reading the internal file.

10.1
Program Text

Program Text (x04bbfe.f90)

10.2
Program Data

Program Data (x04bbfe.d)

10.3
Program Results

Program Results (x04bbfe.r)

© The Numerical Algorithms Group Ltd, Oxford, UK. 2017