On Tuesday, 8 March 2022 at 17:47:47 UTC, BoQsc wrote:
Premise: In D language, only one main(){} function can exist in
a program.
Having two `main()` functions throws an error.
Let's say I want to use some functionality of another program,
but it has a `main(){}`
function. How can I import and use functions without importing
the `main(){}` function?
You'll have to modify the other program to exclude the `main`
function from compilation.
For example, you could use a [`version` condition][1]:
```d
module otherprogram;
version (Otherprogram_NoMain)
{
// no main function
}
else
{
void main(string[] args)
{
// ...
}
}
// other functions...
```
Then, when you're compiling the program that uses it, you can
pass `-version=Otherprogram_NoMain` on the command line:
```
$ dmd -version=Otherprogram_NoMain myprogram.d otherprogram.d
```
This will include the `main` function from `myprogram.d`, but
exclude the one from `otherprogram.d`.
[1]: https://dlang.org/spec/version.html#version
