Manual Reference Pages - system_unsetenv (3m_system)

NAME

system_unsetenv(3f) - [M_system:ENVIRONMENT] delete an environment variable by calling unsetenv(3c) (LICENSE:PD)

Synopsis
Description
Options
Examples
Author
License

SYNOPSIS

subroutine system_unsetenv(name,ierr)

     character(len=*),intent(in)  :: name
     integer,intent(out),optional :: ierr

DESCRIPTION

The system_unsetenv(3f) function deletes the variable name from the environment.

OPTIONS

name name of variable to delete. If name does not exist in the environment, then the function succeeds, and the environment is unchanged.

ierr The system_unsetenv(3f) function returns zero on success, or -1 on error. name is NULL, points to a string of length 0, or contains an ’=’ character. Insufficient memory to add a new variable to the environment.

EXAMPLES

Sample program:

     program demo_system_unsetenv
     use M_system, only : system_unsetenv, system_putenv
     implicit none
     call system_putenv(’GRU=this is the value’)
     write(*,’(a)’)’The variable GRU should be set’
     call execute_command_line(’env|grep GRU’)
     call system_unsetenv(’GRU’)
     write(*,’(a)’)’The variable GRU should not be set’
     call execute_command_line(’env|grep GRU’)
     end program demo_system_unsetenv

AUTHOR

John S. Urban

LICENSE

Public Domain

Nemo Release 3.1

system_unsetenv (3m_system)

March 07, 2025

Generated by manServer 1.08 from 645ec10d-6b84-4c24-b9a1-bfe37be55059 using man macros.

name	name of variable to delete. If name does not exist in the environment, then the function succeeds, and the environment is unchanged.
ierr	The system_unsetenv(3f) function returns zero on success, or -1 on error. name is NULL, points to a string of length 0, or contains an ’=’ character. Insufficient memory to add a new variable to the environment.