This web site contains the commands and results for all the examples
in the paper **"Standardized Mixed Language Programming for Fortran and C"**,
by Bo Einarsson, Richard J. Hanson, and Tim Hopkins. The paper has been
published in the ACM Fortran Forum, December 2009, Vol. 28, Issue 3, pp. 8-22.

Regrettably two links in the references are incorrect. Here are the correct ones.

- Reference 6 The final dot after
`pdf`has to be removed from the actual link. - Reference
9 The tilde symbol
`~`, or`%7E`, is missing in front of`boein`. Also this link has an offending dot at the end.

The paper is also available at the Rogue Wave site.

The paper was presented at the "IFIP Working Group 2.5 Symposium 2009" in Raleigh, N.C.

The example files are obtained by clicking on the file names.
You can download all the files simultaneously by using the compressed file
`all.zip`.

We are here using the Sun system, for other systems the names of the
compilers `f95` and `cc` may have to be modified, for
example to `gfortran` and `gcc`. The name of the Sun computer
in Linköping is "arkimedes".

arkimedes[code]> f95 -V f95: Sun Fortran 95 8.3 SunOS_sparc Patch 127000-01 2007/07/18With the Intel compiler when the main program is in C, it is recommend to link with C instead of with Fortran (with the Portland compiler it is

icc -lifcore <etc.>or

pgcc -pgf90libs <etc.>

arkimedes[code]> f95 CandF.f90 arkimedes[code]> ./a.out Default Fortran and C variables of type integer/int are interoperable Default Fortran and C variables of type real/float are interoperable Default Fortran and C variables of type double precision/double are interoperable Default Fortran and C variables of type logical/boolean are NOT interoperable Default Fortran and C variables of type character/char are interoperable Default Fortran and C variables of type complex/float_complex are interoperableNOTE: The Portland compiler pgf90 8.0-5 did not work properly in this case, a similar error message to the one below was generated. There was however no error message generated from pgf95 9.0-2, since it is logically correct that the

arkimedes[code]> f95 wrapper.f90 ./a.out T T F FNOTE: The Portland compilers pgf90 8.0-5 and pgf95 9.0-2 did not work properly in this case. We got the error message

pgf90 -c wrapper.f90 PGF90-S-0081-Illegal selector - KIND value must be non-negative (wrapper.f90: 5) 0 inform, 0 warnings, 1 severes, 0 fatal for wrapperNegative

arkimedes[code]> f95 f2sam.f90 sam.f90 f2sam.f90: sam.f90: Linking: arkimedes[code]> ./a.out 6 648 Bo G EFortran and C mixed (some systems require linking with C)

arkimedes[code]> cc -c c2sam.c arkimedes[code]> f95 c_sam.f90 sam.f90 c2sam.o c_sam.f90: sam.f90: Linking: arkimedes[code]> ./a.out 6 648 Bo G E

arkimedes[code]> cc -c mlp4.c arkimedes[code]> f95 mlp3.f90 mlp4.o arkimedes[code]> ./a.out 1,3NOTE: This will not work with the Portland compiler, since the Fortran 2003 command

arkimedes[code]> f95 mlp0.f90 mlp2a.f90 mlp0.f90: mlp2a.f90: Linking: arkimedes[code]> ./a.out 786 3.200Fortran and C mixed, elementary version (some systems require linking with C)

arkimedes[code]> cc -c mlp1.c arkimedes[code]> f95 mlp2b.f90 mlp1.o arkimedes[code]> ./a.out 786 3.200Fortran and C mixed, recommended version

arkimedes[code]> cc -c mlp7.c arkimedes[code]> f95 mlp6.f90 mlp7.o arkimedes[code]> ./a.out Fortran has common block /com/ 786 3.20 C gets Common block /com/: 786 3.200000 C gives Common block /com/: 457 17.500000 Fortran has the block /com/ 457 17.50

arkimedes[code]> cc c_mean.c mean.c c_mean.c: mean.c: arkimedes[code]> ./a.out Mean value is 2.000000Fortran and C mixed

arkimedes[code]> cc -c mean.c arkimedes[code]> f95 mlp8.f90 mean.o arkimedes[code]> ./a.out Mean value computed by C is 2.0

arkimedes[code]> cc -c c_sgemm.c arkimedes[code]> f95 sgemm_driver.f90 sgemm.f90 c_sgemm.o sgemm_driver.f90: sgemm.f90: Linking: arkimedes[code]> ./a.out Values of adjoint flags TRANSA, TRANSB = N,n Values of sizes m,n,k,lda,ldb and ldc = 4,3,2,5,3,5 Values of alpha, beta = 5.000000e-01, 1.000000e-01 Value of i,j and A(i,j) = 1, 1, 1.100000e+00 Value of i,j and A(i,j) = 2, 1, 2.100000e+00 Value of i,j and A(i,j) = 3, 1, 3.100000e+00 Value of i,j and A(i,j) = 4, 1, 4.100000e+00 Value of i,j and A(i,j) = 1, 2, 1.200000e+00 Value of i,j and A(i,j) = 2, 2, 2.200000e+00 Value of i,j and A(i,j) = 3, 2, 3.200000e+00 Value of i,j and A(i,j) = 4, 2, 4.200000e+00 Value of i,j and B(i,j) = 1, 1, 1.100000e+00 Value of i,j and B(i,j) = 2, 1, 2.100000e+00 Value of i,j and B(i,j) = 1, 2, 1.200000e+00 Value of i,j and B(i,j) = 2, 2, 2.200000e+00 Value of i,j and B(i,j) = 1, 3, 1.300000e+00 Value of i,j and B(i,j) = 2, 3, 2.300000e+00 Value of i,j and C(i,j) = 1, 1, 1.866000e+00 Value of i,j and C(i,j) = 2, 1, 3.466000e+00 Value of i,j and C(i,j) = 3, 1, 5.066000e+00 Value of i,j and C(i,j) = 4, 1, 6.665999e+00 Value of i,j and C(i,j) = 1, 2, 1.981000e+00 Value of i,j and C(i,j) = 2, 2, 3.681000e+00 Value of i,j and C(i,j) = 3, 2, 5.381001e+00 Value of i,j and C(i,j) = 4, 2, 7.081000e+00 Value of i,j and C(i,j) = 1, 3, 2.096000e+00 Value of i,j and C(i,j) = 2, 3, 3.896000e+00 Value of i,j and C(i,j) = 3, 3, 5.696000e+00 Value of i,j and C(i,j) = 4, 3, 7.495999e+00 Largest difference: 4.7683715E-7 Relative error: 6.361222E-8 arkimedes[code]>NOTE: These last two values are implementation dependent!

In practice also some helper functions have to be called in addition to
`cublasSgemm`. That version in a preliminary form is
`sss_sgemm.f90`.

Only Fortran

boein@sibel:~/Ex8$ g95 enumdefs.f90 f_print_days.f90 f_main.f90 boein@sibel:~/Ex8$ ./a.out month 7 has 31 days month 2 has 28 or 29 days boein@sibel:~/Ex8$Fortran as the main language and routine in C

boein@sibel:~/Ex8$ cc -c c_print_days.c boein@sibel:~/Ex8$ g95 enumdefs.f90 c_print_days.o f_main.f90 boein@sibel:~/Ex8$ ./a.out month 7 has 31 days month 2 has 28 or 29 days boein@sibel:~/Ex8$C as the main language and routine in Fortran (some systems require linking with C)

boein@sibel:~/Ex8$ cc -c c_main.c boein@sibel:~/Ex8$ g95 enumdefs.f90 f_print_days.f90 c_main.o boein@sibel:~/Ex8$ ./a.out month 7 has 31 days month 2 has 28 or 29 days boein@sibel:~/Ex8$It also works with

SUBROUTINE print_days(month) BIND(C, NAME='printDays') 1 Warning: Variable 'month' at (1) is a parameter to the BIND(C) procedure 'print_days' but may not be C interoperable.This seems to be in violation with that the standard guarantees that constants declared as type enumerator will correspond to the same integer type used by C,

A solution was to in the code of `mean.c` replace

extern float mean (float x, float y);withextern "C"followed by parenthesis{ }around the remaining code.

Last modified: November 28, 2012

This website is sponsored by the National Supercomputer Centre in Linköping, Sweden.

Bo Einarsson,bo.g.einarsson@gmail.com