Remove an environment variable
#include <stdlib.h> int unsetenv( const char* name );
Use the -l c option to qcc to link against this library. This library is usually included automatically.
The unsetenv() function removes the environment variable named name from the process's environment. If the named variable doesn't exist, unsetenv() indicates success and doesn't change the environment.
The unsetenv() function manipulates the environment pointed to by the global environ variable.
clearenv(), getenv(), putenv(), setenv()