File Utilities

Helper functions for common file operations.

file_exists

Check whether a file exists on disk.

logical :: exists
exists = file_exists(filepath)

Parameter	Type	Description
filepath	character(*)	Path to the file

Returns: .true. if the file exists, .false. otherwise.

numRows

Count the number of lines (rows) in an open file unit.

integer :: nrows
nrows = numRows(fileunit)

Parameter	Type	Description
fileunit	integer	Fortran file unit number (file must already be open)

Returns: Number of lines in the file (integer). Rewinds the file unit after counting.

Code Example

program main
  use fpl
  implicit none

  character(200) :: filepath
  integer :: nrows
  logical :: exists

  filepath = "database/data.txt"

  ! Check if the file exists
  exists = file_exists(filepath)

  if (exists) then
    write(*,*) "File found: ", trim(filepath)

    ! Open the file and count lines
    open(100, file=filepath, status="old")
    nrows = numRows(100)
    write(*,*) "Number of rows: ", nrows
  else
    write(*,*) "File not found: ", trim(filepath)
  end if
end program main

Compile & Run

gfortran -o fileutils.out fileutils.f90 -I/usr/lib64/gfortran/modules/ -lFPL
./fileutils.out