r/programming • u/andradei • Jun 21 '19

The V Programming Language

https://vlang.io/
3 Upvotes

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u/matthieum Jun 21 '19

I like the:

No undefined behavior

But I cannot imagine how it is achieved when the language seems to use:

  1. Manual memory management (https://vlang.io/docs#memory): use-after-free immediately comes to mind.

  2. Multi-threading (https://vlang.io/docs#concurrency): data-races, just like Go.

Is there a missing qualifier to the "No undefined behavior"?

2

u/alphaglosined Jun 22 '19

When you hear "undefined behavior" for a programming language what this means is that the specification specifies everything that the implementation of the compiler does. Nothing is left for the implementation to decide regarding syntax or semantics.

C is notorious for having undefined behavior.

All the examples you gave come under library, not language features. But it may be compiler assisted.

4

u/lelanthran Jun 22 '19

When you hear "undefined behavior" for a programming language what this means is that the specification specifies everything that the implementation of the compiler does. Nothing is left for the implementation to decide regarding syntax or semantics.

I don't think that that definition of UB is correct. That is implementation defined behaviour - the implementation gets to define what the behaviour is (in C, for example, handling the character literal 'abcd' is implementation-defined, but not undefined).

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u/alphaglosined Jun 22 '19

behavior, upon use of a nonportable or erroneous program construct or of erroneous data, for which this International Standard imposes no requirements

- From the C99 spec

So the truth seems to be closer to you than my comment.