Module: SysBasic

Types for low-level programming and C integration.

This module provides basic types when those types are not platform-dependent. The module SysCTypes contains the platform-dependent declarations for C compatability.

This module also defines the error types syserr and err_t.

When should one use syserr and when should one use err_t? err_t is a system error code (a c_int by a nicer name to indicate its purpose). syserr is an enhanced error that might also include an error message. All user-facing Chapel library code, or user Chapel code, should generally use syserr. When wrapping functions or declaring them in C, use err_t to indicate that a function is returning an error code.

A note about the error code documentation in this file. Error descriptions for system errors are included here for convenience only. Other documentation, such as system man pages or the POSIX specification are the authority on system error codes.

type c_float = real(32)

The type corresponding to a C float

type c_double = real(64)

The type corresponding to a C double

type off_t = int(64)

The type corresponding to C’s off_t

type mode_t = uint(32)

The type corresponding to C’s mode_t

type socklen_t = int(32)

The type corresponding to C’s socklen_t

type syserr

A type storing an error code or an error message. A syserr can be compared using == or != to an err_t (ie integer error code) or to another syserr. A syserr can be cast to or from an err_t. It can be assigned the value of an err_t or another syserr. In addition, syserr can be checked directly in an if statement like so:

var err: syserr;
if err then do writeln("err contains an error, ie err != ENOERR");
if !err then do writeln("err does not contain an error; err == ENOERR");

When a syserr formal has blank intent, the actual is copied to the formal upon a function call and the formal cannot be assigned within the function.

The default value of the syserr type is undefined.

type err_t = c_int

An integral error code. This is really just a c_int, but code is clearer if you use err_t to indicate arguments, variables, and return types that are system error codes.

type fd_t = c_int

A system file descriptior. This is really just a c_int, but code is clearer if you use fd_t to indicate arguments, variables, and return types that are system file descriptors.

const c_nil: c_void_ptr

A Chapel version of a C NULL pointer.

proc is_c_nil(x): bool
Returns:true if the passed value is a NULL pointer (ie 0)
class c_ptr

A local C pointer class used in C integration. This class represents the equivalent to a C language pointer. Instances of this class support assignment to other instances or nil, == or != comparison with a c_void_ptr or with nil, and casting to another c_ptr type or to the c_void_ptr type. In addition, c_ptr works within an if statement directly like so:

var x: c_ptr;
if x then do writeln("x is not nil");
if !x then do writeln("x is nil");
type eltType

The type that this pointer points to

proc c_ptr(i: integral) ref

Retrieve the i’th element (zero based) from a pointer to an array. Does the equivalent of ptr[i] in C.

proc deref() ref

Get element pointed to directly by this pointer. If the pointer refers to an array, this will return ptr[0].

proc c_calloc(type eltType, size: integral)

Allocate memory that is filled with zeros. This memory should eventually be freed with c_free.

Arguments:
  • eltType – the type of the elements to allocate
  • size – the number of elements to allocate
Returns:

a c_ptr(eltType) to allocated memory
proc c_free(data: c_ptr)

Free memory that was allocated with c_free. :arg data: the c_ptr to memory that was allocated

proc c_ptrTo(arr: [])

Returns a c_ptr to a Chapel rectangular array. Note that the existence of this c_ptr has no impact on the lifetime of the array. The returned pointer will be invalid if the original array is freed or even reallocated. Any domain assignment will probably make this c_ptr invalid.

Arguments:arr – the array for which we should retrieve a pointer
Returns:a pointer to the array data
proc c_ptrTo(ref x: ?t): c_ptr(t)

Returns a c_ptr to any Chapel object. Note that the existence of the c_ptr has no impact of the lifetime of the object. In many cases the object will be stack allocated and could go out of scope even if this c_ptr remains.

Arguments:x – the by-reference argument to get a pointer to. The argument should not be an array or domain (there is a different overload for arrays). Records, class instances, integral, real, imag, and complex types are supported.
Returns:a pointer to the argument passed by reference
proc ENOERR

The error code indicating that no error occured (Chapel specific)

proc EEOF

An error code indicating the end of file has been reached (Chapel specific)

proc ESHORT

An error code indicating that the end of file or the end of the input was reached before the requested amount of data could be read. (Chapel specific)

proc EFORMAT

An error code indicating a format error; for example when reading a quoted string literal, this would be returned if we never encountered the opening quote. (Chapel specific)

const E2BIG: err_t

Argument list too long. The number of bytes used for the argument and environment list of the new process exceeded the current limit. (POSIX.1)

const EACCES: err_t

Permission denied. An attempt was made to access a file in a way forbidden by its file access permissions. (POSIX.1)

const EADDRINUSE: err_t

Address already in use. Only one usage of each address is normally permitted. (POSIX.1)

const EADDRNOTAVAIL: err_t

Can’t assign requested address. Normally results from an attempt to create a socket with an address not on this machine. (POSIX.1)

const EAFNOSUPPORT: err_t

Address family not supported by protocol family. An address incompatible with the requested protocol was used. For example, you should not necessarily expect to be able to use NS addresses with ARPA Internet protocols. (POSIX.1)

const EAGAIN: err_t

Resource temporarily unavailable. This is a temporary condition and later calls to the same routine may complete normally. (POSIX.1)

const EALREADY: err_t

Operation already in progress. An operation was attempted on a non-blocking object that already had an operation in progress. (POSIX.1)

const EBADE: err_t

Invalid exchange (linux only)

const EBADF: err_t

Bad file descriptor. A file descriptor argument was out of range, referred to no open file, or a read (write) request was made to a file that was only open for writing (reading). (POSIX.1)

const EBADFD: err_t

File descriptor in bad state (linux only)

const EBADMSG: err_t

Bad message. A corrupted message was detected. (POSIX.1)

const EBADR: err_t

Invalid request descriptor (linux only)

const EBADRQC: err_t

Invalid request code (linux only)

const EBADSLT: err_t

Invalid slot (linux only)

const EBUSY: err_t

Device or resource busy. An attempt to use a system resource which was in use at the time in a manner which would have conflicted with the request. (POSIX.1)

const ECANCELED: err_t

Operation canceled. The scheduled operation was canceled. (POSIX.1)

const ECHILD: err_t

No child processes. A wait or waitpid system call was executed by a process that had no existing or unwaited-for child processes. (POSIX.1)

const ECHRNG: err_t

Channel number out of range (linux only)

const ECOMM: err_t

Communication error on send (linux only)

const ECONNABORTED: err_t

Software caused connection abort. A connection abort was caused internal to your host machine. (POSIX.1)

const ECONNREFUSED: err_t

Connection refused. No connection could be made because the target machine actively refused it. This usually results from trying to connect to a service that is inactive on the foreign host. (POSIX.1)

const ECONNRESET: err_t

Connection reset by peer. A connection was forcibly closed by a peer. This normally results from a loss of the connection on the remote socket due to a timeout or a reboot. (POSIX.1)

const EDEADLK: err_t

Resource deadlock avoided. An attempt was made to lock a system resource that would have resulted in a deadlock situation. (POSIX.1)

const EDESTADDRREQ: err_t

Destination address required. A required address was omitted from an operation on a socket. (POSIX.1)

const EDOM: err_t

Numerical argument out of domain. A numerical input argument was outside the defined domain of the mathematical function. (POSIX.1, C99)

const EDQUOT: err_t

Disc quota exceeded. A write system call to an ordinary file, the creation of a directory or symbolic link, or the creation of a directory entry failed because the user’s quota of disk blocks was exhausted, or the allocation of an inode for a newly created file failed because the user’s quota of inodes was exhausted. (POSIX.1)

const EEXIST: err_t

File exists. An existing file was mentioned in an inappropriate context, for instance, as the new link name in a link system call. (POSIX.1)

const EFAULT: err_t

Bad address. The system detected an invalid address in attempting to use an argument of a call. (POSIX.1)

const EFBIG: err_t

File too large. The size of a file exceeded the maximum. (POSIX.1)

const EHOSTDOWN: err_t

Host is down. A socket operation failed because the destination host was down. (linux, FreeBSD)

const EHOSTUNREACH: err_t

No route to host. A socket operation was attempted to an unreachable host. (POSIX.1)

const EIDRM: err_t

Identifier removed. An IPC identifier was removed while the current process was waiting on it. (POSIX.1)

const EILSEQ: err_t

Illegal byte sequence. While decoding a multibyte character the function came along an invalid or an incomplete sequence of bytes or the given wide character is invalid.

This error might be returned for example in the case of an illegal UTF-8 byte sequence. (POSIX.1, C99)

const EINPROGRESS: err_t

Operation now in progress. An operation that takes a long time to complete (such as a connect system call) was attempted on a non-blocking object. (POSIX.1)

const EINTR: err_t

Interrupted system call. An asynchronous signal (such as SIGINT or SIGQUIT) was caught by the process during the execution of an interruptible function. If the signal handler performs a normal return, the interrupted system call will seem to have returned the error condition. (POSIX.1)

const EINVAL: err_t

Invalid argument. Some invalid argument was supplied. (For example, specifying an undefined signal to a signal system call or a kill system call). (POSIX.1)

const EIO: err_t

Input/output error. Some physical input or output error occurred. This error will not be reported until a subsequent operation on the same file descriptor and may be lost (over written) by any subsequent errors. (POSIX.1)

const EISCONN: err_t

Socket is already connected. A connect system call was made on an already connected socket; or, a sendto or sendmsg system call on a connected socket specified a destination when already connected. (POSIX.1)

const EISDIR: err_t

Is a directory. An attempt was made to open a directory with write mode specified. (POSIX.1)

const EISNAM: err_t

Is a named type file (linux only)

const EKEYEXPIRED: err_t

Key has expired (linux only)

const EKEYREJECTED: err_t

Key was rejected by service (linux only)

const EKEYREVOKED: err_t

Key has been revoked (linux only)

const EL2HLT: err_t

Level 2 halted (linux only)

const EL2NSYNC: err_t

Level 2 not synchronized (linux only)

const EL3HLT: err_t

Level 3 halted (linux only)

const EL3RST: err_t

Level 3 halted (linux only)

const ELIBACC: err_t

Cannot access a needed shared library (linux only)

const ELIBBAD: err_t

Accessing a corrupted shared library (linux only)

const ELIBMAX: err_t

Attempting to link in too many shared libraries (linux only)

const ELIBSCN: err_t

lib section in a.out corrupted (linux only)

const ELIBEXEC: err_t

Cannot exec a shared library directly (linux only)

const ELOOP: err_t

Too many levels of symbolic links. A path name lookup involved more than 32 (MAXSYMLINKS) symbolic links. (POSIX.1)

const EMEDIUMTYPE: err_t

Wrong medium type (linux only)

const EMFILE: err_t

Too many open files. Maximum number of file descriptors allowable in the process has been reached and requests for an open cannot be satisfied until at least one has been closed. The getdtablesize system call will obtain the current limit. (POSIX.1)

Too many links. Maximum allowable hard links to a single file has been exceeded. (POSIX.1)

const EMSGSIZE: err_t

Message too long. A message sent on a socket was larger than the internal message buffer or some other network limit. (POSIX.1)

const EMULTIHOP: err_t

Multihop attempted. (POSIX.1)

const ENAMETOOLONG: err_t

File name too long. A component of a path name exceeded {NAME_MAX} characters, or an entire path name exceeded {PATH_MAX} characters. (POSIX.1)

const ENETDOWN: err_t

Network is down. A socket operation encountered a dead network. (POSIX.1)

const ENETRESET: err_t

Network dropped connection on reset. The host you were connected to crashed and rebooted. (POSIX.1)

const ENETUNREACH: err_t

Network is unreachable. A socket operation was attempted to an unreachable network. (POSIX.1)

const ENFILE: err_t

Too many open files in system. Maximum number of open files allowable on the system has been reached and requests for an open cannot be satisfied until at least one has been closed. (POSIX.1)

const ENOBUFS: err_t

No buffer space available. An operation on a socket or pipe was not performed because the system lacked sufficient buffer space or because a queue was full. (POSIX.1 XSI STREAMS option)

const ENODATA: err_t

No message is available on the STREAM head read queue (POSIX.1)

const ENODEV: err_t

Operation not supported by device. An attempt was made to apply an inappropriate function to a device, for example, trying to read a write-only device such as a printer. (POSIX.1)

const ENOENT: err_t

No such file or directory. A component of a specified pathname did not exist, or the pathname was an empty string. (POSIX.1)

const ENOEXEC: err_t

Exec format error. A request was made to execute a file that, although it has the appropriate permissions, was not in the format required for an executable file. (POSIX.1)

const ENOKEY: err_t

Required key not available (linux only)

const ENOLCK: err_t

No locks available. A system-imposed limit on the number of simultaneous file locks was reached. (POSIX.1)

Link has been severed. (POSIX.1)

const ENOMEDIUM: err_t

No medium found (linux only)

const ENOMEM: err_t

Cannot allocate memory. The new process image required more memory than was allowed by the hardware or by system-imposed memory management constraints. A lack of swap space is normally temporary; however, a lack of core is not. Soft limits may be increased to their corresponding hard limits. (POSIX.1)

const ENOMSG: err_t

No message of desired type. An IPC message queue does not contain a message of the desired type, or a message catalog does not contain the requested message. (POSIX.1)

const ENONET: err_t

Machine is not on the network (linux only)

const ENOPKG: err_t

Package not installed (linux only)

const ENOPROTOOPT: err_t

Protocol not available. A bad option or level was specified in a getsockopt or setsockopt system call. (POSIX.1)

const ENOSPC: err_t

No space left on device. A write system call to an ordinary file, the creation of a directory or symbolic link, or the creation of a directory entry failed because no more disk blocks were available on the file system, or the allocation of an inode for a newly created file failed because no more inodes were available on the file system. (POSIX.1)

const ENOSR: err_t

No STREAM resources (POSIX.1 XSI STREAMS option)

const ENOSTR: err_t

Not a STREAM (POSIX.1 XSI STREAMS option)

const ENOSYS: err_t

Function not implemented. Attempted a system call that is not available on this system. (POSIX.1)

const ENOTBLK: err_t

Block device required. A block device operation was attempted on a non-block device or file. (linux, FreeBSD)

const ENOTCONN: err_t

Socket is not connected. An request to send or receive data was disallowed because the socket was not connected and (when sending on a datagram socket) no address was supplied. (POSIX.1)

const ENOTDIR: err_t

Not a directory. A component of the specified pathname existed, but it was not a directory, when a directory was expected. (POSIX.1)

const ENOTEMPTY: err_t

Directory not empty. A directory with entries other than ‘.’ and ‘..’ was supplied to a remove directory or rename call. (POSIX.1)

const ENOTSOCK: err_t

Socket operation on non-socket. (POSIX.1)

const ENOTSUP: err_t

Operation not supported. The attempted operation is not supported for the type of object referenced. Usually this occurs when a file descriptor refers to a file or socket that cannot support this operation, for example, trying to accept a connection on a datagram socket. (POSIX.1)

const ENOTTY: err_t

Inappropriate ioctl for device. A control function (e.g. ioctl system call) was attempted for a file or special device for which the operation was inappropriate. (POSIX.1)

const ENOTUNIQ: err_t

Name not unique on network (linux only)

const ENXIO: err_t

Device not configured. Input or output on a special file referred to a device that did not exist, or made a request beyond the limits of the device. This error may also occur when, for example, a tape drive is not online or no disk pack is loaded on a drive. (POSIX.1)

const EOPNOTSUPP: err_t

Operation not supported. The attempted operation is not supported for the type of object referenced. Usually this occurs when a file descriptor refers to a file or socket that cannot support this operation, for example, trying to accept a connection on a datagram socket. (POSIX.1)

const EOVERFLOW: err_t

Value too large to be stored in data type. A numerical result of the function was too large to be stored in the caller provided space. (POSIX.1)

const EPERM: err_t

Operation not permitted. An attempt was made to perform an operation limited to processes with appropriate privileges or to the owner of a file or other resources. (POSIX.1)

const EPFNOSUPPORT: err_t

Protocol family not supported. The protocol family has not been configured into the system or no implementation for it exists. (linux, FreeBSD)

const EPIPE: err_t

Broken pipe. A write on a pipe, socket or FIFO for which there is no process to read the data. (POSIX.1)

const EPROTO: err_t

Protocol error. A device or socket encountered an unrecoverable protocol error. (POSIX.1)

const EPROTONOSUPPORT: err_t

Protocol not supported. The protocol has not been configured into the system or no implementation for it exists. (POSIX.1)

const EPROTOTYPE: err_t

Protocol wrong type for socket. A protocol was specified that does not sup- port the semantics of the socket type requested. For example, you cannot use the ARPA Internet UDP protocol with type SOCK_STREAM. (POSIX.1)

const ERANGE: err_t

Result too large. A numerical result of the function was too large to fit in the available space (perhaps exceeded precision). (POSIX.1, C99)

const EREMCHG: err_t

Remote address changed (linux only)

const EREMOTE: err_t

Object is remote (linux only)

const EREMOTEIO: err_t

Remote I/O error (linux only)

const ERESTART: err_t

Interrupted system call should be restarted (linux only)

const EROFS: err_t

Read-only file system. An attempt was made to modify a file or directory on a file system that was read-only at the time. (POSIX.1)

const ESHUTDOWN: err_t

Can’t send after socket shutdown. A request to send data was disallowed because the socket had already been shut down with a previous shutdown system call.

const ESPIPE: err_t

Illegal seek. An lseek system call was issued on a socket, pipe or FIFO. (POSIX.1)

const ESOCKTNOSUPPORT: err_t

Socket type not supported. The support for the socket type has not been configured into the system or no implementation for it exists. (linux, FreeBSD)

const ESRCH: err_t

No such process. No process could be found corresponding to that specified by the given process ID. (POSIX.1)

const ESTALE: err_t

Stale NFS file handle. An attempt was made to access an open file (on an NFS file system) which is now unavailable as referenced by the file descriptor. This may indicate the file was deleted on the NFS server or some other catastrophic event occurred. (POSIX.1)

const ESTRPIPE: err_t

Streams pipe error (linux only)

const ETIME: err_t

Timer expired (POSIX.1 XSI STREAMS option)

const ETIMEDOUT: err_t

Operation timed out. A connect or send system call failed because the connected party did not properly respond after a period of time. (The timeout period is dependent on the communication protocol.) (POSIX.1)

const ETXTBSY: err_t

Text file busy. The new process was a pure procedure (shared text) file which was open for writing by another process, or while the pure procedure file was being executed an open system call requested write access. (POSIX.1)

const EUCLEAN: err_t

Structure needs cleaning (linux only)

const EUNATCH: err_t

Protocol driver not attached (linux only)

const EUSERS: err_t

Too many users. The quota system ran out of table entries. (linux, FreeBSD)

const EWOULDBLOCK: err_t

Operation would block (may be same value as EAGAIN) (POSIX.1)

const EXDEV: err_t

Cross-device link. A hard link to a file on another file system was attempted. (POSIX.1)

const EXFULL: err_t

Exchange full (linux only)