FREAD Function

Reads a record from an external file into the File Data Buffer (FDB).

Category:

External Files

Syntax

FREAD(file-id)

Required Argument

file-id

is a numeric variable that specifies the identifier that was assigned when the file was opened, generally by the FOPEN function.

Details

FREAD returns 0 if the operation was successful, ≠0 if it was not successful. The position of the file pointer is updated automatically after the read operation so that successive FREAD functions read successive file records.

To position the file pointer explicitly, use FNOTE, FPOINT, and FREWIND.

Example

This example assigns the fileref MYFILE to an external file and attempts to open the file. If the file opens successfully, it lists all of the file's records in the log:

%let filrf=myfile;
%let rc=%sysfunc(filename(filrf,
   physical-filename));
%let fid=%sysfunc(fopen(&filrf));
%if &fid > 0 %then
   %do %while(%sysfunc(fread(&fid)) = 0);
      %let rc=%sysfunc(fget(&fid,c,200));
           %put &c;
      %end;
   %let rc=%sysfunc(fclose(&fid));
%let rc=%sysfunc(filename(filrf));