C Library Functions - process_open_read (3)

NAME

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

Synopsis
Description
Options
Examples
See Also
Author
License

SYNOPSIS

subroutine process_open_read(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 read the output of a system command.

  program demo_process_open_read
  use M_process ,only: process_open_read, process_readline
  use M_process ,only: streampointer, process_close
  implicit none
  type(streampointer) :: fp
  ! line of data to read (assumed long enough to hold any output line)
  character(len=4096) :: line
  integer             :: ierr
    ! open process to read from
    call process_open_read(’ls -l’,fp,ierr)
    write(*,*)’READTEST: process is opened with status ’,ierr
    ierr=0
    do while(ierr .eq. 0)
      ! read a line from the process
      call process_readline(line,fp,ierr)
      if(ierr.ne.0)then
        write(*,*)’READTEST: ierr is ’,ierr
        exit
      endif
      write(*,*)’READTEST: ’,trim(line)
    enddo
    call process_close(fp,ierr)
    write(*,*)’READTEST: process closed with status ’,ierr
  end program demo_process_open_read

Sample output:

READTEST: process is opened with status 0 READTEST: total 108 READTEST: -rw-r--r--. 1 urbanjs urbanjs 3731 Oct 17 14:49 build.sh READTEST: -rw-rw-r--. 1 urbanjs urbanjs 56633 Oct 17 14:50 build.sh.log READTEST: drwxrwxr-x. 3 urbanjs urbanjs 4096 Oct 17 14:50 doc READTEST: -rw-rw-r--. 1 urbanjs urbanjs 39459 Oct 17 15:16 M_process.ff READTEST: -rw-rw-r--. 1 urbanjs urbanjs 826 Oct 17 15:17 xx.f90 READTEST: ierr is -1 READTEST: process closed with status 0

AUTHOR

John S. Urban

LICENSE

Public Domain

Nemo Release 3.1

process_open_read (3)

February 23, 2025

Generated by manServer 1.08 from 39753dbb-685e-4e17-b924-4de552d4612f 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)