fgl_getenv()

fgl_getenv() takes a character expression argument which is the name of the variable and returns a character string, which is the value of this environment variable.

The argument of fgl_getenv( ) must be a character expression that returns the name of an environment variable. To evaluate a call to fgl_getenv(), 4GL takes the following actions at runtime:

1. Evaluates the character expression argument of fgl_getenv()

2. Searches among environment variables for the returned value

If the requested variable exists, the function returns it as a character string and then returns control of execution to the calling context. Otherwise, the function returns NULL.

The identifier of an environment variable is not a 4GL expression, so you typically specify the argument as a quoted string or character variable. For example, this call evaluates the DBFORMAT value:

fgl_getenv("DBFORMAT")

 

You can assign the name of the environment variable to a character variable and use that variable as the function argument. If you declare a CHAR or VARCHAR variable called env_var and assign to it the name of an environment variable, fgl_getenv() call could look like this:

fgl_getenv(env_var)

 

If the argument is a character variable, be sure to declare it with sufficient size to store the character value returned by fgl_getenv(), otherwise 4GL will truncate the returned value.

If the specified environment variable is not defined, fgl_getenv() returns a null value. If the environment variable is defined but does not have a value assigned to it, fgl_getenv( ) returns blank spaces.

You can use fgl_getenv( ) anywhere within a 4GL program to examine the value of an environment variable.

The example program below displays the value of the user-specified environment variable. The environment variable is  identified by the env_variable character variable, and its contents are stored in a variable called env_path: