Compile-time functions

V provides several compile-time functions.


$tmpl is a compile-time function that allows you to embed a template into your code.

See Templates for more information.


V can bring in values at compile time from environment variables.

$env('ENV_VAR') can also be used in top-level #flag and #include statements: #flag linux -I $env('JAVA_HOME')/include.

module main fn main() { compile_time_env := $env('ENV_VAR') println(compile_time_env) }

$compile_error and $compile_warn

These two compile time functions are very useful for displaying custom errors/warnings during compile time.

Both receive as their only argument a string literal that contains the message to display:


$if linux { $compile_error('Linux is not supported') } fn main() { }


example.v:4:5: error: Linux is not supported
    2 |
    3 | $if linux {
    4 |     $compile_error('Linux is not supported')
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    5 | }
    6 |