# NAG CL Interfacex04nac

## 1Purpose

x04nac returns a value corresponding to the name of a NAG enumeration member.

## 2Specification

 #include
 int x04nac (const char *enum_string)
The function may be called by the names: x04nac or nag_enum_name_to_value.

## 3Description

x04nac takes a string argument, which must be the name of a NAG enumeration member (e.g., "Nag_ColMajor", "Nag_LogNormal"", etc.), and returns, as an int, the corresponding NAG enumeration member value. If the input string is not the name of a valid NAG enumeration member then the value $-1$ is returned.
The reverse process of converting from enumeration member value to enumeration member name is also available using x04nbc.
Converting enumeration members to and from name and value may be of use when saving a set of problem arguments to file or reading problem arguments from a file for use in an application. In the case of saving problem arguments, any enumeration members to be saved should be saved using their names to be subsequently read as strings. When these strings are read back by an application, x04nac can be used to convert the strings to values suitable for inclusion in NAG Library function calls.
x04nac is also useful when calling NAG Library functions from external application interfaces that do not facilitate enumeration types. In such cases, NAG function calls that expect an enumeration member name as one of its input arguments can pass instead its corresponding integer value following a call to x04nac.

None.

## 5Arguments

1: $\mathbf{enum_string}$const char * Input
On entry: the name of a NAG enumeration member, e.g., "Nag_GeneralMatrix".

## 6Error Indicators and Warnings

If the value $-1$ is returned then the input string is not recognized as a valid NAG enumeration member name.

Not applicable.

## 8Parallelism and Performance

x04nac is not threaded in any implementation.

None.

## 10Example

This example reads problem arguments from input, converts enumeration member names to their correponding value using x04nac, and passes these values to a function for solving a system of equations.

### 10.1Program Text

Program Text (x04nace.c)

### 10.2Program Data

Program Data (x04nace.d)

### 10.3Program Results

Program Results (x04nace.r)