Thread overview
Receiving "pthread_mutexattr_init" during compilation when using FileLogger.
June 07

I getting

import/core/sync/mutex.d(87,36): Error: `pthread_mutexattr_init` cannot be interpreted at compile time, because it has no available source code

compile time error. One of those D exceptions which doesn't say where it happened in your code so you need to comment out the lines that might cause it one by one :D

I found that this was caused by the "FileLogger" which I create at the top of the file. But why?

import std.experimental.logger: FileLogger;

auto fileLogger = new FileLogger("last.log");

Moving the FileLogger instantiation to a function fixes the issue though.

June 07

On Monday, 7 June 2021 at 09:29:08 UTC, tastyminerals wrote:

>

I getting

import/core/sync/mutex.d(87,36): Error: `pthread_mutexattr_init` cannot be interpreted at compile time, because it has no available source code

compile time error. One of those D exceptions which doesn't say where it happened in your code so you need to comment out the lines that might cause it one by one :D

I found that this was caused by the "FileLogger" which I create at the top of the file. But why?

You can't initialize classes at module scope. You can declare them, but then they must be initialized in a function or a module constructor. Normally for a type MyClass in module foo, you'd see an error like this:

Error: variable `foo.MyClass` is a thread-local class and cannot have a static initializer. Use `static this()` to initialize instead.

I guess CTFE runs before the check that catches this, though, and the FileLogger constructor ultimately triggers the error your seeing.

June 07

On Monday, 7 June 2021 at 10:36:23 UTC, Mike Parker wrote:

>

On Monday, 7 June 2021 at 09:29:08 UTC, tastyminerals wrote:

>

I getting

import/core/sync/mutex.d(87,36): Error: `pthread_mutexattr_init` cannot be interpreted at compile time, because it has no available source code

compile time error. One of those D exceptions which doesn't say where it happened in your code so you need to comment out the lines that might cause it one by one :D

I found that this was caused by the "FileLogger" which I create at the top of the file. But why?

You can't initialize classes at module scope. You can declare them, but then they must be initialized in a function or a module constructor. Normally for a type MyClass in module foo, you'd see an error like this:

Error: variable `foo.MyClass` is a thread-local class and cannot have a static initializer. Use `static this()` to initialize instead.

I guess CTFE runs before the check that catches this, though, and the FileLogger constructor ultimately triggers the error your seeing.
I see, I only remember that one cannot create associative arrays in global scope. This is explicitly written in the language reference.
It's interesting how there is no information about class instantiation at module level anywhere in the docs. Even the Ali's book does not explicitly say that you cannot instantiate a class this way. Maybe I missed it but just doing the key search on "scope", "global", "module" in class related chapters didn't give me any results.

June 07

On Monday, 7 June 2021 at 11:29:44 UTC, tastyminerals wrote:

>

On Monday, 7 June 2021 at 10:36:23 UTC, Mike Parker wrote:

>

On Monday, 7 June 2021 at 09:29:08 UTC, tastyminerals wrote:

>

I getting

import/core/sync/mutex.d(87,36): Error: `pthread_mutexattr_init` cannot be interpreted at compile time, because it has no available source code

compile time error. One of those D exceptions which doesn't say where it happened in your code so you need to comment out the lines that might cause it one by one :D

I found that this was caused by the "FileLogger" which I create at the top of the file. But why?

You can't initialize classes at module scope. You can declare them, but then they must be initialized in a function or a module constructor. Normally for a type MyClass in module foo, you'd see an error like this:

Error: variable `foo.MyClass` is a thread-local class and cannot have a static initializer. Use `static this()` to initialize instead.

I guess CTFE runs before the check that catches this, though, and the FileLogger constructor ultimately triggers the error your seeing.
I see, I only remember that one cannot create associative arrays in global scope. This is explicitly written in the language reference.

It's interesting how there is no information about class instantiation at module level anywhere in the docs. Even the Ali's book does not explicitly say that you cannot instantiate a class this way. Maybe I totally missed it but just doing the key search on "scope", "global", "module" in class related chapters didn't give me any results.

June 07

On Monday, 7 June 2021 at 11:31:13 UTC, tastyminerals wrote:

>

It's interesting how there is no information about class instantiation at module level anywhere in the docs. Even the Ali's book does not explicitly say that you cannot instantiate a class this way. Maybe I totally missed it but just doing the key search on "scope", "global", "module" in class related chapters didn't give me any results.

It's covered by this:

https://dlang.org/spec/declaration.html#global_static_init

>

The Initializer for a global or static variable must be evaluatable at compile time. Runtime initialization is done with static constructors.

It obviously could be more explicit. I'll add a note to my todo list to make it so.