eintr

In short, how do you unit test an error condition such as EINTR on a system call. One particular example I'm working on, which could be a case all by itself, is whether it's necessary to call fclose again when it returns EOF with (errno==EINTR). The behavior depends on the implementation of fclose: // Given an open FILE *fp while (fclose(fp)==EOF && errno==EINTR) { errno = 0; } This call can be unsafe if fp freed when EINTR occurs. How can I test the error handling for when (errno==EINTR)? In this particular case, it's not safe to call fclose() again, as the C standard says the stream is

A lot of system calls like close( fd ) Can be interrupted by a signal. In this case usually -1 is returned and errno is set EINTR . The question is what is the right thing to do? Say, I still want this fd to be closed. What I can come up with is: while( close( fd ) == -1 ) if( errno != EINTR ) { ReportError(); break; } Can anybody suggest a better/more elegant/standard way to handle this situation? UPDATE: As noticed by mux, SA_ RESTART flag can be used when installing the signal handler. Can somebody tell me which functions are guaranteed to be restartable on all POSIX systems(not only Linux

I am programming a user application for a embedded Linux system, and I am using the common functions such as open, close, read, ioctl, etc. for the devices. Now, I read about EINTR, indicates that the function was interrupted by a signal, but I am not sure about the implications. In all the example programs I have, sometimes it is done, e.g. ioctl(), sometimes it is not done, e.g. read(). So, I am a little bit confused. When do I preferably check for EINTR and repeat the function call? Yann Droneaud See sigaction : http://pubs.opengroup.org/onlinepubs/009695399/functions/sigaction.html SA