nag_file_line_read (x04bb) is used by NAG Library functions to read formatted records from an external file. All formatted input from an external file by NAG Library functions is performed by calls to nag_file_line_read (x04bb).

References

None.

Parameters

Compulsory Input Parameters

1: $nin$ – int64int32nag_int scalar: 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: $reclen$ – int64int32nag_int scalar: The maximum length of the record in characters.

Optional Input Parameters

None.

Output Parameters

1: $recin$ – string: The first LEN(recin) characters of the record read from unit nin, padded with trailing blanks if the record was shorter than LEN(recin).
2: $ifail$ – int64int32nag_int scalar: $ifail = 0$ unless the function detects an error (see Error Indicators and Warnings).

Error Indicators and Warnings

Errors or warnings detected by the function:

$ifail = 1$: 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.

$ifail = - 399$: Your licence key may have expired or may not have been installed correctly.

$ifail = - 999$: Dynamic memory allocation failed.

Accuracy

Not applicable.

Further Comments

None.

Example

This example program simply illustrates how a formatted record is read from the NAG Toolbox, by first reading it into the character-string recin, used as an internal file, by nag_file_line_read (x04bb) and then reading the internal file.

Open in the MATLAB editor: x04bb_example

function x04bb_example


fprintf('x04bb example results\n\n');

% Filename and asociated unit number
file   = 'foo.data';
iounit = int64(4);

% Open file for writing
mode    = int64(1);
[ifail] = x04ac(iounit, file, mode);

% Write line to file
x04ba(iounit, ' 20  2.996');

% Close file
[ifail] = x04ad(iounit);

% Reopen file for reading
mode    = int64(0);
[ifail] = x04ac(iounit, file, mode);

% Read line from file
reclin = int64(40);
[recin, ifail] = x04bb(iounit, reclin);

disp(recin);

% reclose file
[ifail] = x04ad(iounit);

delete(file)

x04bb example results

 20  2.996

PDF version (NAG web site, 64-bit version, 64-bit version)

Chapter Contents

Chapter Introduction

NAG Toolbox