Webyes, as it is explained in the errno man page and the other replies, errno is a thread local variable.. However, there is a silly detail which could be easily forgotten.Programs should save and restore the errno on any signal handler executing a system call. This is because the signal will be handled by one of the process threads which could overwrite its value. Weberrno is defined by the ISO C standard to be a modifiable lvalue of type int, and must not be explicitly declared; errno may be a macro. errno is thread-local; setting it in one thread does not affect its value in any other thread.
errno - cplusplus.com
WebApr 22, 2024 · Thread Local Storage (TLS) was originally implemented to support pthread-specific data and a per-thread errno variable. errno Variable. The user errno value was … WebIt expands to a static (until C++11) thread-local (since C++11) modifiable lvalue of type int. Several standard library functions indicate errors by writing positive integers to errno. … tonca kozina menu
errno(3) - Linux manual page - Michael Kerrisk
WebMar 15, 2024 · Use the thread_local Type to Declare Variable With Thread Storage Duration. Alternatively, the C language defines a macro expression thread_local to … WebApr 26, 2024 · Allocate thread-local storage and determine TLS offset for all ELF objects with thread-local variables. Apply relocations (using the offsets we just computed) Initialize thread-local storage by copying over from the relevant TLS segments. Adjust protections of the various memory segments. WebWhen using any of the threaded mpms in Apache 2.0 it is important that every function called from Apache be thread safe. When linking in 3rd party extensions it can be difficult to determine whether the resulting server will be thread safe. Casual testing generally won't tell you this either as thread safety problems can lead to subtle race ... tonca kozina urnik