Posix error codes as class of constants. From here: http://fxr.watson.org/fxr/source/sys/errno.h

PosixErrorCodes.php

<?php

class PosixErrorCode
{
    const EPERM           = 1;              /* Operation not permitted */
    const ENOENT          = 2;             /* No such file or directory */
    const ESRCH           = 3;             /* No such process */
    const EINTR           = 4;             /* Interrupted system call */
    const EIO             = 5;             /* Input/output error */
    const ENXIO           = 6;             /* Device not configured */
    const E2BIG           = 7;             /* Argument list too long */
    const ENOEXEC         = 8;             /* Exec format error */
    const EBADF           = 9;             /* Bad file descriptor */
    const ECHILD          = 10;            /* No child processes */
    const EDEADLK         = 11;            /* Resource deadlock avoided */
    const ENOMEM          = 12;            /* Cannot allocate memory */
    const EACCES          = 13;            /* Permission denied */
    const EFAULT          = 14;            /* Bad address */
    const ENOTBLK         = 15;            /* Block device required */
    const EBUSY           = 16;            /* Device busy */
    const EEXIST          = 17;            /* File exists */
    const EXDEV           = 18;            /* Cross-device link */
    const ENODEV          = 19;            /* Operation not supported by device */
    const ENOTDIR         = 20;            /* Not a directory */
    const EISDIR          = 21;            /* Is a directory */
    const EINVAL          = 22;            /* Invalid argument */
    const ENFILE          = 23;            /* Too many open files in system */
    const EMFILE          = 24;            /* Too many open files */
    const ENOTTY          = 25;            /* Inappropriate ioctl for device */
    const ETXTBSY         = 26;            /* Text file busy */
    const EFBIG           = 27;            /* File too large */
    const ENOSPC          = 28;            /* No space left on device */
    const ESPIPE          = 29;            /* Illegal seek */
    const EROFS           = 30;            /* Read-only filesystem */
    const EMLINK          = 31;            /* Too many links */
    const EPIPE           = 32;            /* Broken pipe */
    const EDOM            = 33;            /* Numerical argument out of domain */
    const ERANGE          = 34;            /* Result too large */
    const EAGAIN          = 35;            /* Resource temporarily unavailable */
    const EWOULDBLOCK     = 35;            /* Resource temporarily unavailable */
    const EINPROGRESS     = 36;            /* Operation now in progress */
    const EALREADY        = 37;            /* Operation already in progress */
    const ENOTSOCK        = 38;            /* Socket operation on non-socket */
    const EDESTADDRREQ    = 39;            /* Destination address required */
    const EMSGSIZE        = 40;            /* Message too long */
    const EPROTOTYPE      = 41;            /* Protocol wrong type for socket */
    const ENOPROTOOPT     = 42;            /* Protocol not available */
    const EPROTONOSUPPORT = 43;            /* Protocol not supported */
    const ESOCKTNOSUPPORT = 44;            /* Socket type not supported */
    const EOPNOTSUPP      = 45;            /* Operation not supported */
    const ENOTSUP         = 45;            /* Operation not supported */
    const EPFNOSUPPORT    = 46;            /* Protocol family not supported */
    const EAFNOSUPPORT    = 47;            /* Address family not supported by protocol family */
    const EADDRINUSE      = 48;            /* Address already in use */
    const EADDRNOTAVAIL   = 49;            /* Can't assign requested address */
    const ENETDOWN        = 50;            /* Network is down */
    const ENETUNREACH     = 51;            /* Network is unreachable */
    const ENETRESET       = 52;            /* Network dropped connection on reset */
    const ECONNABORTED    = 53;            /* Software caused connection abort */
    const ECONNRESET      = 54;            /* Connection reset by peer */
    const ENOBUFS         = 55;            /* No buffer space available */
    const EISCONN         = 56;            /* Socket is already connected */
    const ENOTCONN        = 57;            /* Socket is not connected */
    const ESHUTDOWN       = 58;            /* Can't send after socket shutdown */
    const ETOOMANYREFS    = 59;            /* Too many references: can't splice */
    const ETIMEDOUT       = 60;            /* Operation timed out */
    const ECONNREFUSED    = 61;            /* Connection refused */
    const ELOOP           = 62;            /* Too many levels of symbolic links */
    const ENAMETOOLONG    = 63;            /* File name too long */
    const EHOSTDOWN       = 64;            /* Host is down */
    const EHOSTUNREACH    = 65;            /* No route to host */
    const ENOTEMPTY       = 66;            /* Directory not empty */
    const EPROCLIM        = 67;            /* Too many processes */
    const EUSERS          = 68;            /* Too many users */
    const EDQUOT          = 69;            /* Disc quota exceeded */
    const ESTALE          = 70;            /* Stale NFS file handle */
    const EREMOTE         = 71;            /* Too many levels of remote in path */
    const EBADRPC         = 72;            /* RPC struct is bad */
    const ERPCMISMATCH    = 73;            /* RPC version wrong */
    const EPROGUNAVAIL    = 74;            /* RPC prog. not avail */
    const EPROGMISMATCH   = 75;            /* Program version wrong */
    const EPROCUNAVAIL    = 76;            /* Bad procedure for program */
    const ENOLCK          = 77;            /* No locks available */
    const ENOSYS          = 78;            /* Function not implemented */
    const EFTYPE          = 79;            /* Inappropriate file type or format */
    const EAUTH           = 80;            /* Authentication error */
    const ENEEDAUTH       = 81;            /* Need authenticator */
    const EIDRM           = 82;            /* Identifier removed */
    const ENOMSG          = 83;            /* No message of desired type */
    const EOVERFLOW       = 84;            /* Value too large to be stored in data type */
    const ECANCELED       = 85;            /* Operation canceled */
    const EILSEQ          = 86;            /* Illegal byte sequence */
    const ENOATTR         = 87;            /* Attribute not found */
    const EDOOFUS         = 88;            /* Programming error */
    const EBADMSG         = 89;            /* Bad message */
    const EMULTIHOP       = 90;            /* Multihop attempted */
    const ENOLINK         = 91;            /* Link has been severed */
    const EPROTO          = 92;            /* Protocol error */
    const ENOTCAPABLE     = 93;            /* Capabilities insufficient */
    const ECAPMODE        = 94;            /* Not permitted in capability mode */
    const ENOTRECOVERABLE = 95;            /* State not recoverable */
    const EOWNERDEAD      = 96;            /* Previous owner died */
    const ELAST           = 96;            /* Must be equal largest errno */
}