The original approach is to execute a FILE LOG statement prior to each diagnostic message, and then re-execute the FILE statement for the output file after the diagnostic message is complete.

data _null_;
  file "c:\temp\Dinosaur\PutLogFile1.csv" dsd;
  if _n_=1 then put "Name,Age,Height";
  set sashelp.class;
  if age lt 12 then do;
    file log;
    put "Student age is less than 12 ... Please verify for " name= age=;
    file "c:\temp\Dinosaur\PutLogFile1.csv";
  end;
  put Name Age Height;
run;

SAS Log

1078  data _null_;
1079    file "c:\temp\Dinosaur\PutLogFile1.csv" dsd;
1080    if _n_=1 then put "Name,Age,Height";
1081    set sashelp.class;
1082    if age lt 12 then do;
1083      file log;
1084      put "Student age is less than 12 ... Please verify for " name= age=;
1085      file "c:\temp\Dinosaur\PutLogFile1.csv";
1086    end;
1087    put Name Age Height;
1088  run;
 
NOTE: The file "c:\temp\Dinosaur\PutLogFile1.csv" is:
      Filename=c:\temp\Dinosaur\PutLogFile1.csv,
      RECFM=V,LRECL=256,File Size (bytes)=0,
      Last Modified=14May2008:20:21:17,
      Create Time=05Aug2007:18:06:13
 
Student age is less than 12 ... Please verify for Name=Joyce Age=11
Student age is less than 12 ... Please verify for Name=Thomas Age=11
NOTE: 20 records were written to the file "c:\temp\Dinosaur\PutLogFile1.csv".
      The minimum record length was 10.
      The maximum record length was 15.
NOTE: There were 19 observations read from the data set SASHELP.CLASS.
 

An alternate approach is to use the PUTLOG statement for the diagostic messages.

data _null_;
  file "c:\temp\Dinosaur\PutLogFile2.csv" dsd;
  if _n_=1 then put "Name,Age,Height";
  set sashelp.class;
  if age lt 12 then
    putlog "Student age is less than 12 ... Please verify for " name= age=;
  put Name Age Height;
run;

SAS Log

1100  data _null_;
1101    file "c:\temp\Dinosaur\PutLogFile2.csv" dsd;
1102    if _n_=1 then put "Name,Age,Height";
1103    set sashelp.class;
1104    if age lt 12 then
1105      putlog "Student age is less than 12 ... Please verify for " name= age=;
1106    put Name Age Height;
1107  run;
 
NOTE: The file "c:\temp\Dinosaur\PutLogFile2.csv" is:
      Filename=c:\temp\Dinosaur\PutLogFile2.csv,
      RECFM=V,LRECL=256,File Size (bytes)=0,
      Last Modified=14May2008:20:21:17,
      Create Time=05Aug2007:18:07:45
 
Student age is less than 12 ... Please verify for Name=Joyce Age=11
Student age is less than 12 ... Please verify for Name=Thomas Age=11
NOTE: 20 records were written to the file "c:\temp\Dinosaur\PutLogFile2.csv".
      The minimum record length was 10.
      The maximum record length was 15.
NOTE: There were 19 observations read from the data set SASHELP.CLASS.
 

Advantages of the alternate approach:

• The PUTLOG statement writes only to the SAS log, eliminating any potential interference with the external output file.
• The only FILE statement required corresponds to the external output file. The original approach may require the main FILE statement to be executed multiple times.

Disadvantages of the alternate approach:

• The PUTLOG statement writes only to the SAS log, so you cannot redirect diagnostic messages to a secondary external file. You must specify multiple FILE statements, one for the main external file and one for the diagnostics.