UPDATE: Please see below the EDITS made to this post! The post itself will remain the original one for the sake of keeping with the logic of the discussion!
I'm trying to write a test program that opens a user-specified filename - containing two data columns and a line describing how many lines (after that line) contain data, so it may generate two arrays with that specific size to read and write it. The specified file structure is depicted below in this answer. I've been using the ideas laid out here to create variable size arrays:
program char
implicit none
character(len = 200) :: filename;
integer :: line_number;
print*,'What is the file name?'
read(*,*) filename
print*, 'the file is: ',filename
open(1,file=filename, status = 'old')
read(1,*)line_number
call read_data(line_number)
end program char
subroutine read_data(N)
implicit none
integer, intent (in) :: N;
integer :: imax, i;
real,dimension(N) :: a,b;
imax=N+1
do i=2,imax
read(1,*)a(i),b(i)
write(1,*)a(i),b(i)
end do
end subroutine read_data
My test file is called 'matrix.dat' (which I do not wish to hardcode in the file!) and has the following structure, as mentioned previously: first line describes the number of lines of the matrix, the remaining lines are data columns separated solely by a space.
9
1.0 1.1
2.0 2.2
3.0 3.3
4.0 4.4
5.0 5.5
6.0 6.6
7.0 7.7
8.0 8.8
9.0 9.9
During compilation, the compiler churns out some rather unusual errors, which I do not understand.
Strelok@Yggdrasil:~$ gcc char.f95 -o char.exe
/usr/bin/ld: /tmp/cciriF9x.o: in function `read_data_':
char.f95:(.text+0x105): undefined reference to `_gfortran_st_read'
/usr/bin/ld: char.f95:(.text+0x135): undefined reference to `_gfortran_transfer_real'
/usr/bin/ld: char.f95:(.text+0x165): undefined reference to `_gfortran_transfer_real'
/usr/bin/ld: char.f95:(.text+0x174): undefined reference to `_gfortran_st_read_done'
/usr/bin/ld: char.f95:(.text+0x1af): undefined reference to `_gfortran_st_write'
/usr/bin/ld: char.f95:(.text+0x1df): undefined reference to `_gfortran_transfer_real_write'
/usr/bin/ld: char.f95:(.text+0x20f): undefined reference to `_gfortran_transfer_real_write'
/usr/bin/ld: char.f95:(.text+0x21e): undefined reference to `_gfortran_st_write_done'
/usr/bin/ld: /tmp/cciriF9x.o: in function `MAIN__':
char.f95:(.text+0x295): undefined reference to `_gfortran_st_write'
/usr/bin/ld: char.f95:(.text+0x2b0): undefined reference to `_gfortran_transfer_character_write'
/usr/bin/ld: char.f95:(.text+0x2bf): undefined reference to `_gfortran_st_write_done'
/usr/bin/ld: char.f95:(.text+0x2fa): undefined reference to `_gfortran_st_read'
/usr/bin/ld: char.f95:(.text+0x318): undefined reference to `_gfortran_transfer_character'
/usr/bin/ld: char.f95:(.text+0x327): undefined reference to `_gfortran_st_read_done'
/usr/bin/ld: char.f95:(.text+0x362): undefined reference to `_gfortran_st_write'
/usr/bin/ld: char.f95:(.text+0x37d): undefined reference to `_gfortran_transfer_character_write'
/usr/bin/ld: char.f95:(.text+0x39b): undefined reference to `_gfortran_transfer_character_write'
/usr/bin/ld: char.f95:(.text+0x3aa): undefined reference to `_gfortran_st_write_done'
/usr/bin/ld: char.f95:(.text+0x421): undefined reference to `_gfortran_st_open'
/usr/bin/ld: char.f95:(.text+0x45c): undefined reference to `_gfortran_st_read'
/usr/bin/ld: char.f95:(.text+0x47a): undefined reference to `_gfortran_transfer_integer'
/usr/bin/ld: char.f95:(.text+0x489): undefined reference to `_gfortran_st_read_done'
/usr/bin/ld: /tmp/cciriF9x.o: in function `main':
char.f95:(.text+0x4bb): undefined reference to `_gfortran_set_args'
/usr/bin/ld: char.f95:(.text+0x4cc): undefined reference to `_gfortran_set_options'
collect2: error: ld returned 1 exit status
Any help would be greatly appreciated. Also, if anyone can provide me with a way of having the program evaluate the columns sizes automatically instead of having me declare it a priori, I would be most grateful!
EDIT #1: Following @Swift - Friday Pie suggestion, I recompiled using gfortran, and it compiled fine. HOWEVER, upon execution of the file, I got the following error message:
strelok@Yggdrasil:~$ gfortran char.f95 -o char.exe
strelok@Yggdrasil:~$ ./char.exe
What is the file name?
matrix.dat
the file is: matrix.dat
At line 23 of file char.f95 (unit = 1, file = 'matrix.dat')
Fortran runtime error: End of file
Error termination. Backtrace:
#0 0x7faccc5c0d0a
#1 0x7faccc5c1819
#2 0x7faccc5c24ef
#3 0x7faccc802b3b
#4 0x7faccc7fbcf6
#5 0x7faccc7fcc99
#6 0x55f77a465341
#7 0x55f77a4656a4
#8 0x55f77a4656dd
#9 0x7faccc3d60b2
#10 0x55f77a46514d
#11 0xffffffffffffffff
EDIT #2: Source code has been modified, as suggested by @albert and @Ian Bush. It should now read as depicted below.
program char
implicit none
character(len = 200) :: filename;
integer :: line_number;
print*,'What is the file name?'
read(*,*) filename
print*, 'the file is: ',filename
open(10,file=filename, status = 'old')
read(10,*)line_number
call read_data(line_number)
end program char
subroutine read_data(N)
implicit none
integer, intent (in) :: N;
integer :: imax, i;
real,dimension(N) :: a,b;
read(10,*)
do i=1,N
read(10,*) a(i),b(i)
write(*,*) a(i),b(i)
end do
end subroutine read_data
Compilation errors are gone, but during execution of the program, there's an error:
strelok@Yggdrasil:~$ ./char.exe
What is the file name?
matrix.dat
the file is: matrix.dat
1.00000000 1.10000002
At line 22 of file char_original.f95 (unit = 10, file = 'matrix.dat')
Fortran runtime error: End of file
Error termination. Backtrace:
#0 0x7f714b51dd0a
#1 0x7f714b51e819
#2 0x7f714b51f4ef
#3 0x7f714b75fb3b
#4 0x7f714b758cf6
#5 0x7f714b759c99
#6 0x55bb2ff56382
#7 0x55bb2ff566e5
#8 0x55bb2ff5671e
#9 0x7f714b3330b2
#10 0x55bb2ff5614d
#11 0xffffffffffffffff
