errorp
NAME
errorp() - determine whether or not a given variable is an error code
SYNOPSIS
int errorp( mixed arg );
DESCRIPTION
Returns 1 if 'arg' is an integer that is an error code.
Eventually efuns will be modified to return standard error codes so
that code like this will be possible:
if (errorp(result = efun_call()))
printf("error = %d\n", result);
In future, there will also be a perror(result) efun to return error
string that goes with a particular error integer.
SEE ALSO
nullp(3), undefinedp(3)