The global error list sys_errlist indexed by errno can
be used to obtain the error message without the newline.
The largest message number provided in the table is
sys_nerr -1. Be careful when directly accessing this list
because new error values may not have been added to
When a system call fails, it usually returns -1 and sets
the variable errno to a value describing what went wrong.
(These values can be found in <errno.h>.) Many library
functions do likewise. The function perror() serves to
translate this error code into human-readable form. Note
that errno is undefined after a successful library call:
this call may well change this variable, even though it
succeeds, for example because it internally used some
other library function that failed. Thus, if a failing
call is not immediately followed by a call to perror, the
value of errno should be saved.