According to fputs own documentation, yes, EOF does set errno. The man pages infer it indirectly as opposed to stating it outright, which hopefully will be amended. The function fputs returns an integer that will either be positive on success or EOF on failure. So the key to error handling fputs is to setup a code block that checks the return value of fputs as it is being called. The following is a snippet of how I've been taught to handle fputs errors.
if (fputs(buffer, stdout) == EOF)
{
fprintf(stderr, "fputs returned EOF: %s\n", strerror(errno));
// .. and now do whatever cleanup you need to do.
// or be lazy and exit(-1)
}
Here I am writing the contents of buffer to standard output and checking to see if fputs returns EOF. EOF indicates an error code was set, so as long as you follow the documentation on the man pages for fputs, you should be able to create a bunch of if statements to check the various error codes errno can be set to.
(1) What is buffer? Some character array I declared elsewhere.
(2) What does fprintf do? It prints output to a passed in file descriptor, which is in this case standard error (stderr... it prints to console like stdout, but for errors).
(3) What is strerror? It is a function defined in the string.h header that prints error information for the passed in error code. It has information for every single error code that errno can be set to. The header string.h should NOT be confused with strings.h, which is a BSD linux header file that does not contain strerror(3).
Edit: Ok, I messed up. You were looking for an answer on fgets, not fputs.
To check for an error on fgets, do the following
if (fgets(buffer, BUF_SIZE, myFile) == NULL)
{
// print out error as a string to stderr
fprintf(stderr, "fgets error occurred: %s\n", strerror(errno));
// do cleanup
}
// special: you also need to check errno AFTER the if statement...
The thing is, the only way you are getting an error on this is if the stream becomes unreadable, which is either due to permissions or trying to read something that is in write mode. In the case of a network, it may be possible for something to cut off your connection in the middle of reading, in which case you need to check the error code after the fgets if statement as well. But it will set the error code if something went wrong.
At least that is if the man pages are correct. See the linux man pages for more details. Only error code that can be set is the "I can't read this thing" code, which is errno == EBADF