ERRNO(3)

NAME
errno - number of last error

SYNOPSIS
#include <errno.h>

extern int errno;

DESCRIPTION
The integer errno is set by system calls (and some library functions) to indicate what went wrong. Its value is significant only when the call returned an error (usually -1), and a library function that does succeed is allowed to change errno. Sometimes, when -1 is also a legal return value one has to zero errno before the call in order to detect possible errors. POSIX lists the following symbolic error names.

E2BIG
    Arg list too long

EACCES
    Permission denied

EAGAIN
    Resource temporarily unavailable

EBADF
    Bad file descriptor

EBUSY
    Resource busy

ECHILD
    No child processes

EDEADLK
    Resource deadlock avoided

EDOM
    Domain error

EEXIST
    File exists

EFAULT
    Bad address

EFBIG
    File too large

EINTR
    Interrupted function call

EINVAL
    Invalid argument

EIO Input/output error

EISDIR
    Is a directory

EMFILE
    Too many open files

EMLINK
    Too many links

ENAMETOOLONG
    Filename too long

ENFILE
    Too many open files in system

ENODEV
    No such device

ENOENT
    No such file or directory

ENOEXEC
    Exec format error

ENOLCK
    No locks available

ENOMEM
    Not enough space

ENOSPC
    No space left on device

ENOSYS
    Function not implemented

ENOTDIR
    Not a directory

ENOTEMPTY
    Directory not empty

ENOTTY
    Inappropriate I/O control operation

ENXIO
    No such device or address

EPERM
    Operation not permitted

EPIPE
    Broken pipe

ERANGE
    Result too large

EROFS
    Read-only file system

ESPIPE
    Invalid seek

ESRCH
    No such process

EXDEV
    Improper link

SEE ALSO
perror(3)