Handling Operating System Variation
When writing cross-platform applications or libraries, it is often necessary to allow for differences between operating systems. The variable Sys.KERNEL
can be used to handle such cases. There are several functions in the Sys
module intended to make this easier, such as isunix
, islinux
, isapple
, isbsd
, isfreebsd
, and iswindows
. These may be used as follows:
if Sys.iswindows()
windows_specific_thing(a)
end
Note that islinux
, isapple
, and isfreebsd
are mutually exclusive subsets of isunix
. Additionally, there is a macro @static
which makes it possible to use these functions to conditionally hide invalid code, as demonstrated in the following examples.
Simple blocks:
ccall((@static Sys.iswindows() ? :_fopen : :fopen), ...)
Complex blocks:
@static if Sys.islinux()
linux_specific_thing(a)
else
generic_thing(a)
end
When chaining conditionals (including if
/elseif
/end
), the @static
must be repeated for each level (parentheses optional, but recommended for readability):
@static Sys.iswindows() ? :a : (@static Sys.isapple() ? :b : :c)