FORTRAN IO OPERATION

[Madhubalan_R_]

Hi all I am using the following code to create a new file PROGRAM TEST_IO INTEGER*4 UNIT,IOS OPEN (UNIT=119, FILE = '$HOME/compile.log', IOSTAT = IOS, - STATUS = 'NEW', RECL = 132, FORM = 'FORMATTED', - RECORDTYPE = 'VARIABLE', ORGANIZATION = 'SEQUENTIAL', - CARRIAGECONTROL = 'FORTRAN') PRINT *,IOS END PROGRAM Here HOME(/home/my_name) is an environment variable.When I execute this code I am always getting the IOS as 46.Without using a function to get the value of the environment variable, Can I solve this issue?

[mecej4 · Accepted solution]

You should not expect Fortran (or C, etc.) to do symbol substitutions or globbing in the same manner that we expect the Linux shell to do. You can call a library function to obtain the values of environment variables. See https://software.intel.com/en-us/node/526226; you can do

USE IFPORT   

character(len=50) :: buf

...

call getenv('HOME',buf)
OPEN (UNIT=119, FILE = trim(buf)//'/compile.log', IOSTAT = IOS,
- STATUS = 'NEW', RECL = 132, FORM = 'FORMATTED',
- RECORDTYPE = 'VARIABLE', ORGANIZATION = 'SEQUENTIAL',
- CARRIAGECONTROL = 'FORTRAN')

...

[Madhubalan_R_]

Thanks you so much.

[FortranFan]

mecej4 wrote:

You should not expect Fortran (or C, etc.) to do symbol substitutions or globbing in the same manner that we expect the Linux shell to do. You can call a library function to obtain the values of environment variables. See https://software.intel.com/en-us/node/526226; you can do

USE IFPORT   

character(len=50) :: buf

...

call getenv('HOME',buf)
OPEN (UNIT=119, FILE = trim(buf)//'/compile.log', IOSTAT = IOS,
- STATUS = 'NEW', RECL = 132, FORM = 'FORMATTED',
- RECORDTYPE = 'VARIABLE', ORGANIZATION = 'SEQUENTIAL',
- CARRIAGECONTROL = 'FORTRAN')

...

Standard Fortran subroutine (i.e., intrinsic procedure) GET_ENVIRONMENT_VARIABLE would now be preferable over an Intel extension of getenv:

See https://software.intel.com/en-us/node/580640.

With GET_ENVIRONMENT_VARIABLE, one does not need to include "USE IFPORT" statement.

[jimdempseyatthecove]

One caveat on the suggestion is if the environment variable 'HOME' is not specified, then the filename '/compile.log' places the log file in the root directory. It might be better to test buf for all blanks and/or with trailing '/'.

BUF = ADJUSTL(BUF)
IF(BUF.EQ.' ') THEN
  BUF = './'
ELSE
  IF(BUF(LEN_TRIM(BUF):LEN_TRIM(BUF)) .NE. '/') BUF = TRIM(BUF)//'/'
ENDIF

Consider adjusting the above to handle '\' as separator.

Jim Dempsey