On 5 jun, 06:15, Charles Sanders <[EMAIL PROTECTED]> wrote: > luis wrote: > > I'm using ctypes to call afortrandllfrom python. I have no problems > > passing integer and double arryas, but I have an error with str arrys. > > For example: > > [snip] > > I do not know about MicrosoftFortrancompilers (your mention > ofdllindicates you are probably using MS), nor much about > Python, but the C equivalent of a givenFortrancall is operating > system and compiler dependent. You should consult theFortran > compiler manual for the compiler used to create theDLL. > > Despite this, many (but not all) C toFortraninterfaces have > the following characteristics > > + C name isFortranname in lower case > +FortranREAL, DOUBLE PRECISION, INTEGER etc parameters > are pointers to the parameter in C, ie float*, etc > +FortranREAL etc arrays are pointers in C (same as > C arrays decay to pointers). > +FortranCHARACTER and CHARACTER arrays are passed as TWO > parameters, one a pointer to the start of the variable > or array, and the other the length as an integer, not > a pointer. The length parameters follow all other > parameters, in order of the character variables/arrays. > > Variations I have seen (all on Unix) include using upper case > instead of lower, prepending (or postpending) an underscore (or > other character(s)) to the subroutine or function name, and > using special "character descriptors" (packing address and > length into one "word") for character variables. There are > almost certainly more variations that I have not seen. > > For example, given aFORTRANdeclaration > > SUBROUTINE X( CV, RV, CA, N ) > CHARACTER*(*) CV > REAL RV > CHARACTER*(*) CA(*) > INTEGER N > > The C equivalent is likely to be > > void x( char *pcv, float *prv, char *pca, int *pn, > int lv, int la) > > Where lv will hold the length of cv and la the length of > each element of ca (required to be the same for all elements > of the array).Fortranuses fixed length character strings, > padded with blanks. > > Given the error message > > > ValueError: Procedure probably called with not enough > > arguments (4 bytes missing) > > I suspect that yourFortrancompiler is one of the many which > do this, and the missing 4 bytes are the integer length of > each element of the character array. > > Also, I noticed you seem to be passing an array of character > pointers rather than an array of characters. It is doubtful thatFortrancan > handle this. You will probably have to pad the strings > to a maximal length with spaces, concatanate then into one big > string, and pass this by reference together with their padded > length. YourFortranmay (but probably won't) have extensions > that allow you to pass an array of character pointers. > > Charles
The solution proposed by Jugoslav Dujic, from comp lang fortran is #Python script calling fortran subroutine from ctypes import * ap = windll.LoadLibrary(self.locationDll) ap.TEST_02.restype=None myCadena='D:\BBDD\PythonScripts\pru.txt' strLen=len(myCadena) pf_myCadena = c_char_p(myCadena) pf_srLen = c_int(strLen) ap.TEST_02(pf_myCadena,pf_srLen) !fortran dll subroutine TEST_02(s) !DEC$ ATTRIBUTES DLLEXPORT :: TEST_02 !DEC$ATTRIBUTES REFERENCE:: s !INTEGER(4):: n CHARACTER(*):: s open (unit=31,file=trim(s)) write(31,'(f0.1)') 1.0 write(31,*) trim(s) write(31,'(i0)') len_trim(s) close(31) return END subroutine Regards -- http://mail.python.org/mailman/listinfo/python-list
