# NAG CL Interfacee04wlc (nlp2_​option_​double_​get)

Settings help

CL Name Style:

## 1Purpose

e04wlc is used to get the value of a double optional parameter. e04wlc can be used before or after calling e04wdc.

## 2Specification

 #include
 void e04wlc (const char *string, double *rvalue, Nag_E04State *state, NagError *fail)
The function may be called by the names: e04wlc, nag_opt_nlp2_option_double_get or nag_opt_nlp_option_get_double.

## 3Description

e04wlc obtains the current value of a double option. For example
`e04wlc ("LU Factor Tolerance", &factol, &state, &fail);`
will result in the value of the optional parameter ${\mathbf{LU Factor Tolerance}}$ being output in factol.
A complete list of optional parameters, their abbreviations, synonyms and default values is given in Section 12 in e04wdc.

None.

## 5Arguments

1: $\mathbf{string}$const char * Input
On entry: a single valid keyword of a double optional parameter (as described in Section 12 in e04wdc).
2: $\mathbf{rvalue}$double * Output
On exit: the double value associated with the keyword in string.
3: $\mathbf{state}$Nag_E04State * Communication Structure
state contains internal information required for functions in this suite. It must not be modified in any way.
4: $\mathbf{fail}$NagError * Input/Output
The NAG error argument (see Section 7 in the Introduction to the NAG Library CL Interface).

## 6Error Indicators and Warnings

NE_ALLOC_FAIL
Dynamic memory allocation failed.
See Section 3.1.2 in the Introduction to the NAG Library CL Interface for further information.
On entry, argument $⟨\mathit{\text{value}}⟩$ had an illegal value.
NE_E04_OPTION_INVALID
The supplied option string is invalid. Check that the keywords are neither ambiguous nor misspelt. The option string is ‘$⟨\mathit{\text{value}}⟩$’.
NE_E04WCC_NOT_INIT
The initialization function e04wcc has not been called.
NE_INTERNAL_ERROR
An internal error has occurred in this function. Check the function call and any array sizes. If the call is correct then please contact NAG for assistance.
See Section 7.5 in the Introduction to the NAG Library CL Interface for further information.
NE_NO_LICENCE
Your licence key may have expired or may not have been installed correctly.
See Section 8 in the Introduction to the NAG Library CL Interface for further information.

Not applicable.