Manual Reference Pages - execute_command_line (3)
execute_command_line(3f) - [FORTRAN:INTRINSIC:SYSTEM ENVIRONMENT] Execute a shell command
CONTENTS
Syntax
Description
Arguments
Example
Note
Standard
Class
SYNTAX
call execute_command_line(command [, wait, exitstat, cmdstat, cmdmsg ])
DESCRIPTION
The COMMAND argument is passed to the shell and executed. (The shell is generally sh(1) on Unix systems, and cmd.exe on Windows.) If WAIT is present and has the value false, the execution of the command is asynchronous if the system supports it; otherwise, the command is executed synchronously.
The three last arguments allow the user to get status information. After synchronous execution, EXITSTAT contains the integer exit code of the command, as returned by SYSTEM. CMDSTAT is set to zero if the command line was executed (whatever its exit status was). CMDMSG is assigned an error message if an error has occurred.
Note that the system call need not be thread-safe. It is the responsibility of the user to ensure that the system is not called concurrently if required.When the command is executed synchronously, EXECUTE_COMMAND_LINE returns after the command line has completed execution. Otherwise, EXECUTE_COMMAND_LINE returns without waiting.
ARGUMENTS
COMMAND - a default CHARACTER scalar containing the command line to be executed. The interpretation is programming-environment dependent. WAIT - (Optional) a default LOGICAL scalar. If WAIT is present with the value .false., and the processor supports asynchronous execution of the command, the command is executed asynchronously; otherwise it is executed synchronously. EXITSTAT - (Optional) an INTEGER of the default kind with intent(INOUT). If the command is executed synchronously, it is assigned the value of the processor-dependent exit status. Otherwise, the value of EXITSTAT is unchanged. CMDSTAT - (Optional) an INTEGER of default kind with intent(INOUT). If an error condition occurs and CMDSTAT is not present, error termination of execution of the image is initiated. It is assigned the value -1 if the processor does not support command line execution, a processor-dependent positive value if an error condition occurs, or the value -2 if no error condition occurs but WAIT is present with the value false and the processor does not support asynchronous execution.Otherwise it is assigned the value 0.
CMDMSG - (Optional) a CHARACTER scalar of the default kind. It is an INTENT (INOUT) argument.If an error condition occurs, it is assigned a processor-dependent explanatory message.Otherwise, it is unchanged.
EXAMPLE
Sample program:
program demo_exec integer :: icall execute_command_line("external_prog.exe", exitstat=i) print *, "Exit status of external_prog.exe was ", i
call execute_command_line("reindex_files.exe", wait=.false.) print *, "Now reindexing files in the background" end program demo_exec
NOTE
Because this intrinsic is making a system call, it is very system dependent.Its behavior with respect to signaling is processor dependent.In particular, on POSIX-compliant systems, the SIGINT and SIGQUIT signals will be ignored, and the SIGCHLD will be blocked.As such, if the parent process is terminated, the child process might not be terminated alongside.
STANDARD
[[Fortran 2008]] and later
CLASS
Subroutine
| execute_command_line (3) | March 18, 2019 |
