I'm stuck on this little problem. I was wondering if it is possible to pass a variable of a bash-shell script to a f90 code?
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2Wonder no more, it certainly is possible.High Performance Mark– High Performance Mark2015-04-12 16:44:32 +00:00Commented Apr 12, 2015 at 16:44
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3 Answers
I am pretty sure it was discussed here before, but I cannot find an exact duplicate.
You can pass arguments directly as arguments to the program
./program arg1 arg2
you can retrieve the values in the program as character strings in Fortran 2003 using subroutines GET_COMMAND ARGUMENT and COMMAND_ARGUMENT_COUNT. Click on the links to get useful examples.
In older Fortran you have to use non-standard extensions, such as the subroutines GETARG and IARGC.
You can also read an environment variable which was set in the script
VAR1 = ...
VAR2 = ...
./program
using Fortran 2003 subroutine GET_ENVIRONMENT_VARIABLE. In older Fortran you have to use some non-standard extension, such as the subroutine GETENV.
You can also redirect a file to the standard input of the program and read the data using the READ statement.
answered Apr 12, 2015 at 17:55
Vladimir F Героям слава
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1 Comment
High Performance Mark
Yes, this has been discussed many times here on SO. Even one of my own modest contributions (stackoverflow.com/questions/13843772/…) touches on how to read command line arguments with
get_command_argument.You can choose between the following possibilities:
- In bash use export of the variable
myvar="example"; export myvar - Add them as argument to the fortran call
myFortran "${myvar}" - Write them to a file and read the file
Worst solution, just to mention them all - Write it to stdin of fortran program
echo "${myvar}" | myFortran
3 Comments
Vladimir F Героям слава
Maybe worth mentioning how to get that value in the Fortran program. Actually in strictly standard Fortran 90 the 1 and 2 are not possible, although there are on-standard extensions for that.
Walter A
@Vladimir Thanks for adding thr Fortran details.
Simon Schneider
The export in combination with getenv worked for me, thanks a lot!
And you can use the following procedures to read an environment variable: get_environment_variable
https://gcc.gnu.org/onlinedocs/gfortran/GET_005fENVIRONMENT_005fVARIABLE.html
Or read the number and value of the command argument: command_argument_count,get_command_argument. See:
https://gcc.gnu.org/onlinedocs/gfortran/Intrinsic-Procedures.html#Intrinsic-Procedures
