Error handling

In libuv errors are negative numbered constants. As a rule of thumb, whenever there is a status parameter, or an API functions returns an integer, a negative number will imply an error.

When a function which takes a callback returns an error, the callback will never be called.

Note

Implementation detail: on Unix error codes are the negated errno (or -errno), while on Windows they are defined by libuv to arbitrary negative numbers.

Error constants

UV_E2BIG

argument list too long

UV_EACCES

permission denied

UV_EADDRINUSE

address already in use

UV_EADDRNOTAVAIL

address not available

UV_EAFNOSUPPORT

address family not supported

UV_EAGAIN

resource temporarily unavailable

UV_EAI_ADDRFAMILY

address family not supported

UV_EAI_AGAIN

temporary failure

UV_EAI_BADFLAGS

bad ai_flags value

UV_EAI_BADHINTS

invalid value for hints

UV_EAI_CANCELED

request canceled

UV_EAI_FAIL

permanent failure

UV_EAI_FAMILY

ai_family not supported

UV_EAI_MEMORY

out of memory

UV_EAI_NODATA

no address

UV_EAI_NONAME

unknown node or service

UV_EAI_OVERFLOW

argument buffer overflow

UV_EAI_PROTOCOL

resolved protocol is unknown

UV_EAI_SERVICE

service not available for socket type

UV_EAI_SOCKTYPE

socket type not supported

UV_EALREADY

connection already in progress

UV_EBADF

bad file descriptor

UV_EBUSY

resource busy or locked

UV_ECANCELED

operation canceled

UV_ECHARSET

invalid Unicode character

UV_ECONNABORTED

software caused connection abort

UV_ECONNREFUSED

connection refused

UV_ECONNRESET

connection reset by peer

UV_EDESTADDRREQ

destination address required

UV_EEXIST

file already exists

UV_EFAULT

bad address in system call argument

UV_EFBIG

file too large

UV_EHOSTUNREACH

host is unreachable

UV_EINTR

interrupted system call

UV_EINVAL

invalid argument

UV_EIO

i/o error

UV_EISCONN

socket is already connected

UV_EISDIR

illegal operation on a directory

UV_ELOOP

too many symbolic links encountered

UV_EMFILE

too many open files

UV_EMSGSIZE

message too long

UV_ENAMETOOLONG

name too long

UV_ENETDOWN

network is down

UV_ENETUNREACH

network is unreachable

UV_ENFILE

file table overflow

UV_ENOBUFS

no buffer space available

UV_ENODEV

no such device

UV_ENOENT

no such file or directory

UV_ENOMEM

not enough memory

UV_ENONET

machine is not on the network

UV_ENOPROTOOPT

protocol not available

UV_ENOSPC

no space left on device

UV_ENOSYS

function not implemented

UV_ENOTCONN

socket is not connected

UV_ENOTDIR

not a directory

UV_ENOTEMPTY

directory not empty

UV_ENOTSOCK

socket operation on non-socket

UV_ENOTSUP

operation not supported on socket

UV_EPERM

operation not permitted

UV_EPIPE

broken pipe

UV_EPROTO

protocol error

UV_EPROTONOSUPPORT

protocol not supported

UV_EPROTOTYPE

protocol wrong type for socket

UV_ERANGE

result too large

UV_EROFS

read-only file system

UV_ESHUTDOWN

cannot send after transport endpoint shutdown

UV_ESPIPE

invalid seek

UV_ESRCH

no such process

UV_ETIMEDOUT

connection timed out

UV_ETXTBSY

text file is busy

UV_EXDEV

cross-device link not permitted

UV_UNKNOWN

unknown error

UV_EOF

end of file

UV_ENXIO

no such device or address

too many links

API

const char* uv_strerror(int err)

Returns the error message for the given error code. Leaks a few bytes of memory when you call it with an unknown error code.

const char* uv_err_name(int err)

Returns the error name for the given error code. Leaks a few bytes of memory when you call it with an unknown error code.

int uv_translate_sys_error(int sys_errno)

Returns the libuv error code equivalent to the given platform dependent error code: POSIX error codes on Unix (the ones stored in errno), and Win32 error codes on Windows (those returned by GetLastError() or WSAGetLastError()).

If sys_errno is already a libuv error, it is simply returned.

Changed in version 1.10.0: function declared public.