question about keeeping reference to toStringz()

[Ali Çehreli]

On 05/30/2018 01:09 PM, Dr.No wrote:

 > consider a C function with this prototype:
 >> void foo(const char *baa);
 >
 > Does it means I should do:
 >
 >> string s = ...;
 >> auto cstring = s.toStringz;
 >> foo(cstring);
 >
 > rather just:
 >
 >> foo(s.toStringz);
 >
 > ?

It depends. cstring method above is not sufficient if cstring's life is 
shorter than the C library's use:

void bar() {
     string s = ...;
     auto cstring = s.toStringz;
     foo(cstring);

} // <- cstring is gone

What if the library saved that pointer while performing foo()?

If cstring is in module-scope or in a container (e.g. an array) that's 
in module-scope then it's fine. But then, you would have to remove it 
from that container when the C library does not need that pointer anymore.

Ali