GETENVQQ

Module

USE IFPORT

result = GETENVQQ (varname,value)

Results

The result type is INTEGER(4). The result is the length of the string returned in value. Zero is returned if the given variable is not defined.

GETENVQQ searches the list of environment variables for an entry corresponding to varname. Environment variables define the environment in which a process executes. For example, the LIB environment variable defines the default search path for libraries to be linked with a program.

Note that some environment variables may exist only on a per-process basis and may not be present at the command-line level.

GETENVQQ uses the C runtime routine getenv and SETENVQQ uses the C runtime routine _putenv. From the C documentation:

getenv and _putenv use the copy of the environment pointed to by the global variable _environ to access the environment. getenv operates only on the data structures accessible to the run-time library and not on the environment segment created for the process by the operating system.

In a program that uses the main function, _environ is initialized at program startup to settings taken from the operating system's environment.

Changes made outside the program by the console SET command, for example, SET MY_VAR=ABCDE, will be reflected by GETENVQQ.

GETENVQQ and SETENVQQ will not work properly with the Windows* APIs GetEnvironmentVariable and SetEnvironmentVariable.

Example

!  Program to demonstrate GETENVQQ and SETENVQQ
USE IFPORT
USE IFCORE
INTEGER(4) lenv, lval
CHARACTER(80) env, val, enval
WRITE (*,900) ' Enter environment variable name to create, &
                modify, or delete: '
lenv = GETSTRQQ(env)
IF (lenv .EQ. 0) STOP
WRITE (*,900) ' Value of variable (ENTER to delete): '
lval = GETSTRQQ(val)
IF (lval .EQ. 0) val = ' '
enval = env(1:lenv) // '=' // val(1:lval)
IF (SETENVQQ(enval)) THEN
  lval = GETENVQQ(env(1:lenv), val)
  IF (lval .EQ. 0) THEN
    WRITE (*,*) 'Can''t get environment variable'
  ELSE IF (lval .GT. LEN(val)) THEN
    WRITE (*,*) 'Buffer too small'
  ELSE
    WRITE (*,*) env(:lenv), ': ', val(:lval)
    WRITE (*,*) 'Length: ', lval
  END IF
ELSE
  WRITE (*,*) 'Can''t set environment variable'
END IF
900  FORMAT (A, \)
END