7.8 PAUSE Statement

The PAUSE statement temporarily suspends program execution until the user or system resumes execution. The PAUSE statement is an obsolescent feature in Fortran 90, which has been deleted in Fortran 95. Compaq Fortran fully supports features deleted in Fortran 95.

The PAUSE statement takes the following form:

 PAUSE [pause-code]

pause-code

Is an optional message. It can be either of the following:

• A scalar character constant of type default character.

• A string of up to six digits; leading zeros are ignored. (Fortran 90 and FORTRAN 77 limit digits to five.)

Rules and Behavior

If you specify pause-code, the PAUSE statement displays the specified message and then displays the default prompt.

If you do not specify pause-code, the system displays the following default message:

FORTRAN PAUSE

The following prompt is then displayed:

• On OpenVMS systems, the system prompt

• On Tru64 UNIX systems:

  PAUSE prompt>
  

• On Windows NT and Windows 9* systems:

  Fortran Pause - Enter command<CR> or <CR> to continue.
  

The effect of PAUSE differs depending on whether the program is an interactive or batch process, as follows:

• If a program is an interactive process, the program is suspended until you enter one of the following commands:

  • CONTINUE resumes execution at the next executable statement.

  • DEBUG resumes execution under control of the OpenVMS Debugger.

  • EXIT terminates execution.

  In general, most other commands also terminate execution.

• If a program is a batch process, the program is not suspended. If you specify a value for pause-code, this value is written to SYS$OUTPUT.

The effect of PAUSE differs depending on whether the program is a foreground or background process, as follows:

• If a program is a foreground process, the program is suspended until you enter the CONTINUE command. Execution then resumes at the next executable statement.

  Any other command terminates execution.

• If a program is a background process, the behavior depends on stdin, as follows:

  • If stdin is redirected from a file, the system displays the following (after the pause code and prompt):

    To continue from background, execute 'kill -15 n'
    

    In this message, n is the process id of the program.

  • If stdin is not redirected from a file, the program becomes a suspended background job, and you must specify fg to bring the job into the foreground. You can then enter a command to resume or terminate processing.

Anything else is treated as a DOS command and is executed by a system( ) call. The program loops, letting you execute multiple DOS commands, until a blank line is entered. Execution then resumes at the next executable statement.

Examples

The following examples show valid PAUSE statements:

PAUSE 701
PAUSE 'ERRONEOUS RESULT DETECTED'

For More Information:

• On stdin, see your user manual or programmer's guide.

• On obsolescent features in Fortran 90 and Fortran 95, as well as features deleted in Fortran 95, see Appendix A.