Additional Topics > External Development Guide > Obsolete Internal Interfaces > Obsolete Error Handling API

# Obsolete Error Handling API

The following variables can be accessed only on UNIX. These variables have been superseded by the functions listed in “Functions for Returning System Variables”, which are available on all platforms. In all cases, these variables should be considered READ-ONLY:

IDL System Variable | Internal Variable | Type
--- | --- | ---
!DIR | IDL_SysvDir | IDL_STRING
!VERSION.ARCH | IDL_SysvVersion.arch | IDL_STRING
!VERSION.OS | IDL_SysvVersion.os | IDL_STRING
!VERSION.OS_FAMILY | IDL_SysvVersion.os_family | IDL_STRING
!VERSION.RELEASE | IDL_SysvVersion.release | IDL_STRING
!ERR | IDL_SysvErrCode | IDL_LONG
!ERROR | IDL_SysvErrorCode | IDL_LONG
!ORDER | IDL_SysvOrder | IDL_LONG

!ORDER IDL_SysvOrder IDL_LONG

In addition, the following function has been superseded by the

IDL_SysvErrorCodeValue( ) function:

### IDL_LONG IDL_SysvErrCodeValue(void)

This function returns the value of !ERR.