which functions can take over the standard ones in a multi-thread program?

[Jack]

Hi,
I hear about poeple say standard library functions are not usable in a
multi-thread program.
Such as printf....asctime, what mostly people do in order to tackle this
problem?
I mean to use which other functions are acceptable by C++?
Thanks
Jack

[Ulrich Eckhardt]

Post by Jack
I hear about poeple say standard library functions are not usable in a
multi-thread program.

Nonsense. However, neither C nor C++ standards mention threads at all, so
their behaviour in a multithreaded program are formally not defined.

Post by Jack
Such as printf....asctime, what mostly people do in order to tackle this
problem?

asctime() for example returns a pointer to a static buffer, which means its
content may be overwritten by a different thread. There are thread-safe
versions around using a thread-local buffer, alternatively there is
asctime_r() for example. In any case, those deficiencies are documented
including suggested alternatives. Just search the web.

Uli

[Martin B.]

Post by Ulrich Eckhardt

Post by Jack
I hear about poeple say standard library functions are not usable in a
multi-thread program.

Nonsense. However, neither C nor C++ standards mention threads at all, so
their behaviour in a multithreaded program are formally not defined.

Post by Jack
Such as printf....asctime, what mostly people do in order to tackle this
problem?

asctime() for example returns a pointer to a static buffer, which means its
content may be overwritten by a different thread. There are thread-safe
versions around using a thread-local buffer, ...

AFAIK, with Visual Studio linking with (the default) Multi-threaded
Runtime Library will have all std-c library function thread-safe.

br,
Martin