NAG Library Routine Document

M01NCF

1  Purpose

2  Specification

3  Description

4  References

5  Parameters

1:     $\mathrm{VALID}$ – LOGICALInput

On entry: if VALID is set to .TRUE. parameter checking will be performed. If VALID is set to .FALSE. M01NCF will be called without parameter checking, which includes checking that array CH is sorted in ascending order and the routine will return with $\mathbf{IFAIL}=\mathbf{0}$. See Section 9 for further details.

2:     $\mathrm{CH}\left(\mathbf{M2}\right)$ – CHARACTER(*) arrayInput

On entry: elements M1 to M2 contain character data to be searched.

Constraint: elements M1 to M2 of CH must be sorted in ascending order. The length of each element of CH must not exceed $255$. Trailing space characters are ignored.

3:     $\mathrm{M1}$ – INTEGERInput

On entry: the index of the first element of CH to be searched.

Constraint: $\mathbf{M1}\ge 1$.

4:     $\mathrm{M2}$ – INTEGERInput

On entry: the index of the last element of CH to be searched.

Constraint: $\mathbf{M2}\ge \mathbf{M1}$.

5:     $\mathrm{ITEM}$ – CHARACTER(*)Input

On entry: the sought-after item. Trailing space characters are ignored.

6:     $\mathrm{IFAIL}$ – INTEGERInput/Output

On entry: IFAIL must be set to $0$, $-1\text{ or }1$. If you are unfamiliar with this parameter you should refer to Section 3.3 in the Essential Introduction for details.

For environments where it might be inappropriate to halt program execution when an error is detected, the value $-1\text{ or }1$ is recommended. If the output of error messages is undesirable, then the value $1$ is recommended. Otherwise, if you are not familiar with this parameter, the recommended value is $0$. When the value $-\mathbf{1}\text{ or }\mathbf{1}$ is used it is essential to test the value of IFAIL on exit.

On exit: $\mathbf{IFAIL}=\mathbf{0}$ unless the routine detects an error or a warning has been flagged (see Section 6).

6  Error Indicators and Warnings

$\mathbf{IFAIL}=2$

On entry, CH must be sorted in ascending order: $\mathbf{CH}\text{ element }〈\mathit{\text{value}}〉>\text{ element }〈\mathit{\text{value}}〉$.

$\mathbf{IFAIL}=3$

On entry, $\mathbf{M1}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{M1}\ge 1$.

$\mathbf{IFAIL}=4$

On entry, $\mathbf{M1}=〈\mathit{\text{value}}〉$, $\mathbf{M2}=〈\mathit{\text{value}}〉$.
Constraint: $\mathbf{M2}\ge \mathbf{M1}$.

$\mathbf{IFAIL}=5$

On entry, the length of each element of CH must be at most $255$: maximum string length $=〈\mathit{\text{value}}〉$.

$\mathbf{IFAIL}=-99$

An unexpected error has been triggered by this routine. Please contact NAG.

See Section 3.8 in the Essential Introduction for further information.

$\mathbf{IFAIL}=-399$

Your licence key may have expired or may not have been installed correctly.

See Section 3.7 in the Essential Introduction for further information.

$\mathbf{IFAIL}=-999$

Dynamic memory allocation failed.

See Section 3.6 in the Essential Introduction for further information.

7  Accuracy

8  Parallelism and Performance

9  Further Comments

10  Example

10.1  Program Text

Program Text (m01ncfe.f90)

10.2  Program Data

Program Data (m01ncfe.d)

10.3  Program Results

Program Results (m01ncfe.r)