Read

• For typed files, reads a file component into a variable.
• For text files, reads one or more values into one or more variables

Declaration

Typed files: procedure Read(F , V1 [, V2,...,Vn ] );

Text files: procedure Read( [ var F: Text; ] V1 [, V2,...,Vn ] );

Target

Windows, Real, Protected

Remarks

With a type string variable

• Read reads all characters up to, but not including, the next end-of-line marker or until Eof(F) becomes True; it does not skip to the next line after reading. If the resulting string is longer than the maximum length of the string variable, it is truncated.
• After the first Read, each subsequent Read will see the end-of-line marker and return a zero-length string.

Use multiple Readln calls to read successive string values. When the extended syntax is enabled, Read can read null-terminated strings into zero-based character arrays.

With type integer or type real variables

• Read will skip any blanks, tabs, or end-of-line markers preceding the numeric string.
• If the numeric string does not conform to the expected format, an I/O error occurs, otherwise the value is assigned to the variable.
• The next Read will start with the blank, tab or end-of-line marker that terminated the numeric string.

See Also

ReadKey

Readln

Write

Writeln

Sample Code

{Eof.PAS}
{Sample code for the Eof, Read, and Write functions (text files).}
{ For Windows: }
{ uses WinCrt, WinDos; }

var
  F: Text;
  Ch: Char;
begin
  { Get file to read from command line }
  Assign(F, ParamStr(1));
  Reset(F);
  while not Eof(F) do
  begin
    Read(F, Ch);
    Write(Ch);  { Dump text file }
  end;
end.