Hi Alex, > Can anyone point me to some GNU/GCC documentation (or have any experience) regarding this ? Is is safe to assume that both the code generated by gcc and the libgcc_s.a libraries are thread-safe ? You¹ve sort of asked a loaded question. GCC is as thread-safe as the programmers who use threading in their C code, make their code thread-safe. GCC supports some thread-safe idioms, such as making sure that static variables are thread-safe initialized, but there is a caveat race condition for a series of static variables that may cause a surprise. Ultimately, the thread-safe issues for GCC are not GCC problems, rather they are C problems. Some C library routines are *NOT* thread-safe, often because they are not re-entrant. C is not a thread-safe language. If you read the C specification (ISO 9899), you will find that on the issue of threading facilities, the specification is silent. All threading solutions for C are add-on libraries, and as such to use to threading facilities you (the developer) need to abide by that threading system¹s constraints, conventions and disciplines. By ³disciplines², that means that the developers who use those threading facilities must be meticulous to adhere to those threading constraints. Violation of those constraints will mean a threading-related bug in your code*. C++ runs into the same morass of threading problems. There are some nice platform neutral threading abstractions in C++, such as provided by Boost or RogueWave, but ultimately C++ (ISO 14882) does not provide a threading solution as part of the specification. There are languages that have strong threading guarantees, because threading is built into the specification. Languages such as Ada, Java, Haskell, D programming language, or Erlang. Detractors of threading in those languages will point out that their solutions have shortcomings or inefficiencies (especially on some platforms moreso than others). A threading library solution, such as used in C and C++, give flexibility, at the expense of portability (using the OS¹s threading facilities directly), or require using a platform neutral abstraction (such as Boost or RogueWave). And, as mentioned, demand a very high rigor of meticulousness regardless if using native threading facilities or a threading abstraction. Sincerely, <Eljay * In C, threading bugs are far too often very hard to debug. Does not matter if it is GCC or some other compiler.
