Life time of the string referenced by a __FILE__ preprocessor statement.

[Johan Lindh]

This is somewhat obscure, and I'm not sure if the question is valid in
comp.lang.c. If it isn't, please ignore it.

In a C program, the pointer resulting from a __FILE__ is stored.
The pointer refers to a normal string constant (I think).
Does the standard say anything about when that constant is destroyed,
thus rendering any use of the stored pointer undefined behavior?

I guess the question might be simplified into:

"What's the lifetime of a string constant?"

My gut reaction is of course "Until the program ends".

Regards,

Johan

 

[Jeremy Yallop]

In a C program, the pointer resulting from a __FILE__ is stored.
The pointer refers to a normal string constant (I think).

I'm not quite sure what you mean. __FILE__ is textually replaced with
a string literal (i.e. an anonymous null-terminated array of char).

I guess the question might be simplified into:

"What's the lifetime of a string constant?"

My gut reaction is of course "Until the program ends".

Right. A string literal object has "static" storage duration, which
means:

Its lifetime is the entire execution of the program and its stored
value is initialized only once, prior to program startup.
[C99 6.2.4]

Jeremy.