Manual Reference Pages - process_open_write (3)

NAME

process_open_write(3fm) - [M_process] open a process for writing using a POSIX interface (LICENSE:PD)

Synopsis
Description
Options
Examples
See Also
Author
License

SYNOPSIS

subroutine process_open_write(cmd,fp,ierr)

      character(len=*)    :: cmd
      type(streampointer) :: fp
      integer             :: ierr

DESCRIPTION

The M_process Fortran procedures use the ISO_C_BINDING interface to define Fortran-callable versions of the C procedures popen(3c)/pclose(3c) and fgets(3c)/fputs(3c). A set of record-oriented wrapper routines are then used to create a simple Fortran-callable interface.
A POSIX C interface is generally available but may require using a Linux subwindow or an application such as CygWin on MSWindows platforms.
See "M_process" for an extended description.

OPTIONS

cmd command passed to system to start process

fp C file pointer returned by process_open_*()

ierr error flag returned.

o process_writeline(3f) : negative indicates an error

o process_readline(3f) : Non-zero indicates an error

maximum character value length is currently 4096

EXAMPLES

This example shows a routine to write lines to the stdin of a system process

  program demo_process_open_write
  use, intrinsic :: iso_fortran_env, only : &
  & stdin=>input_unit, &
  & stdout=>output_unit, &
  & stderr=>error_unit
  use M_process ,ONLY: process_open_write, process_writeline
  use M_process ,ONLY: streampointer, process_close
  implicit none
  type(streampointer) :: fp
  ! line of data to write
  character(len=4096) :: line
  integer             :: ierr
  integer             :: i
    ! open process to write to
    call process_open_write(’cat -n’,fp,ierr)
    write(stdout,*)’OPENWTEST: process is opened with status ’,ierr
    ! remember C and Fortran I/O are often independent of each other
    flush(stdout)
    ierr=0
    line=’xxxxxxxxxxxxxxxxxxxxxxxxxxx’
    do i=1,10
      ! write a line to the process
      call process_writeline(trim(line),fp,ierr)
      if(ierr.lt.0)then
        write(stdout,*)’OPENWTEST: ierr is ’,ierr
        exit
      endif
    enddo
    call process_close(fp,ierr)
    write(stdout,*)’OPENWTEST: process closed with status ’,ierr
  end program demo_process_open_write

Sample output:

>OPENWTEST: process is opened with status 0 > 1 xxxxxxxxxxxxxxxxxxxxxxxxxxx > 2 xxxxxxxxxxxxxxxxxxxxxxxxxxx > 3 xxxxxxxxxxxxxxxxxxxxxxxxxxx > 4 xxxxxxxxxxxxxxxxxxxxxxxxxxx > 5 xxxxxxxxxxxxxxxxxxxxxxxxxxx > 6 xxxxxxxxxxxxxxxxxxxxxxxxxxx > 7 xxxxxxxxxxxxxxxxxxxxxxxxxxx > 8 xxxxxxxxxxxxxxxxxxxxxxxxxxx > 9 xxxxxxxxxxxxxxxxxxxxxxxxxxx > 10 xxxxxxxxxxxxxxxxxxxxxxxxxxx >OPENWTEST: process closed with status 0

AUTHOR

John S. Urban

LICENSE

Public Domain

process_open_write (3)

March 11, 2021

Generated by manServer 1.08 from 1b6e8d83-a954-4d67-90b2-aafe298fe926 using man macros.

o	PIPES: pipe(3c), popen(3c), pclose(3c), fflush(3c)
o	NAMED PIPES: mkfifo(3c), mknod(3c)
o	SUBPROCESSES: fork(3c)
o	OTHER: fflush(3c)

[UP]