Errors

ArgumentError(msg)

The arguments passed to a function are invalid. msg is a descriptive error message.

AssertionError([msg])

The asserted condition did not evaluate to true. Optional argument msg is a descriptive error string.

Examples

julia> @assert false "this is not true"
ERROR: AssertionError: this is not true

AssertionError is usually thrown from @assert.

BoundsError([a],[i])

An indexing operation into an array, a, tried to access an out-of-bounds element at index i.

Examples

julia> A = fill(1.0, 7);

julia> A[8]
ERROR: BoundsError: attempt to access 7-element Vector{Float64} at index [8]


julia> B = fill(1.0, (2,3));

julia> B[2, 4]
ERROR: BoundsError: attempt to access 2×3 Matrix{Float64} at index [2, 4]


julia> B[9]
ERROR: BoundsError: attempt to access 2×3 Matrix{Float64} at index [9]

DivideError()

Integer division was attempted with a denominator value of 0.

Examples

julia> 2/0
Inf

julia> div(2, 0)
ERROR: DivideError: integer division error
Stacktrace:
[...]

DomainError(val)
DomainError(val, msg)

The argument val to a function or constructor is outside the valid domain.

Examples

julia> sqrt(-1)
ERROR: DomainError with -1.0:
sqrt was called with a negative real argument but will only return a complex result if called with a complex argument. Try sqrt(Complex(x)).
Stacktrace:
[...]

ErrorException(msg)

Generic error type. The error message, in the .msg field, may provide more specific details.

Examples

julia> ex = ErrorException("I've done a bad thing");

julia> ex.msg
"I've done a bad thing"

InexactError(name::Symbol, T, val)

Cannot exactly convert val to type T in a method of function name.

Examples

julia> convert(Float64, 1+2im)
ERROR: InexactError: Float64(1 + 2im)
Stacktrace:
[...]

InterruptException()

The process was stopped by a terminal interrupt (CTRL+C).

Note that, in Julia script started without -i (interactive) option, InterruptException is not thrown by default. Calling Base.exit_on_sigint(false) in the script can recover the behavior of the REPL. Alternatively, a Julia script can be started with

julia -e "include(popfirst!(ARGS))" script.jl

to let InterruptException be thrown by CTRL+C during the execution.

MethodError(f, args)

A method with the required type signature does not exist in the given generic function. Alternatively, there is no unique most-specific method.

OutOfMemoryError()

An operation allocated too much memory for either the system or the garbage collector to handle properly.

OverflowError(msg)

The result of an expression is too large for the specified type and will cause a wraparound.

ReadOnlyMemoryError()

An operation tried to write to memory that is read-only.

StackOverflowError()

The function call grew beyond the size of the call stack. This usually happens when a call recurses infinitely.

TypeError(func::Symbol, context::AbstractString, expected::Type, got)

A type assertion failure, or calling an intrinsic function with an incorrect argument type.

UndefKeywordError(var::Symbol)

The required keyword argument var was not assigned in a function call.

Examples

julia> function my_func(;my_arg)
           return my_arg + 1
       end
my_func (generic function with 1 method)

julia> my_func()
ERROR: UndefKeywordError: keyword argument `my_arg` not assigned
Stacktrace:
 [1] my_func() at ./REPL[1]:2
 [2] top-level scope at REPL[2]:1

UndefRefError()

The item or field is not defined for the given object.

Examples

julia> struct MyType
           a::Vector{Int}
           MyType() = new()
       end

julia> A = MyType()
MyType(#undef)

julia> A.a
ERROR: UndefRefError: access to undefined reference
Stacktrace:
[...]

UndefVarError(var::Symbol, [scope])

A symbol in the current scope is not defined.

Examples

julia> a
ERROR: UndefVarError: `a` not defined in `Main`

julia> a = 1;

julia> a
1

CompositeException

Wrap a Vector of exceptions thrown by a Task (e.g. generated from a remote worker over a channel or an asynchronously executing local I/O write or a remote worker under pmap) with information about the series of exceptions. For example, if a group of workers are executing several tasks, and multiple workers fail, the resulting CompositeException will contain a "bundle" of information from each worker indicating where and why the exception(s) occurred.

DimensionMismatch([msg])

The objects called do not have matching dimensionality. Optional argument msg is a descriptive error string.

EOFError()

No more data was available to read from a file or stream.

KeyError(key)

An indexing operation into an AbstractDict (Dict) or Set like object tried to access or delete a non-existent element.

MissingException(msg)

Exception thrown when a missing value is encountered in a situation where it is not supported. The error message, in the msg field may provide more specific details.

ProcessFailedException

Indicates problematic exit status of a process. When running commands or pipelines, this is thrown to indicate a nonzero exit code was returned (i.e. that the invoked process failed).

StringIndexError(str, i)

An error occurred when trying to access str at index i that is not valid.

SystemError(prefix::AbstractString, [errno::Int32])

A system call failed with an error code (in the errno global variable).

TaskFailedException

This exception is thrown by a wait(t) call when task t fails. TaskFailedException wraps the failed task t.