petsc-3.14.5 2021-03-03
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# PetscOptionsEList

Puts a list of option values that a single one may be selected from Logically Collective on the communicator passed in PetscOptionsBegin()

### Synopsis

    #include "petscsys.h"
    PetscErrorCode  PetscOptionsEList(const char opt[],const char ltext[],const char man[],const char *const *list,PetscInt ntext,const char currentvalue[],PetscInt *value,PetscBool  *set)

### Input Parameters

| opt | - option name
| ltext | - short string that describes the option
| man | - manual page with additional information on option
| list | - the possible choices (one of these must be selected, anything else is invalid)
| ntext | - number of choices
| currentvalue | - the current value; caller is responsible for setting this value correctly. Normally this is done with

                    PetscOptionsElist(..., obj->value,&value,&flg);

                    if (flg) {

### Output Parameter

| value | - the index of the value to return
| set | - PETSC_TRUE if found, else PETSC_FALSE

### Notes

Must be between a PetscOptionsBegin() and a PetscOptionsEnd()

If the user does not supply the option at all value is NOT changed. Thus you should ALWAYS initialize value if you access it without first checking if the set flag is true.

See PetscOptionsFList() for when the choices are given in a PetscFunctionList()

### See Also

PetscOptionsGetInt(), PetscOptionsGetReal(),
PetscOptionsHasName(), PetscOptionsGetIntArray(), PetscOptionsGetRealArray(), PetscOptionsBool(), PetscOptionsName(), PetscOptionsBegin(), PetscOptionsEnd(), PetscOptionsHead(), PetscOptionsStringArray(),PetscOptionsRealArray(), PetscOptionsScalar(), PetscOptionsBoolGroupBegin(), PetscOptionsBoolGroup(), PetscOptionsBoolGroupEnd(), PetscOptionsFList(), PetscOptionsEnum()

### Level

intermediate

### Location

src/sys/objects/aoptions.c

### Examples

src/dm/field/tutorials/ex1.c.html
src/ksp/ksp/tutorials/ex29.c.html
src/ksp/ksp/tutorials/ex32.c.html
src/ksp/ksp/tutorials/ex71.c.html
src/ksp/ksp/tutorials/ex73.c.html
src/snes/tutorials/ex12.c.html
src/snes/tutorials/ex17.c.html
src/snes/tutorials/ex62.c.html
src/snes/tutorials/ex77.c.html
src/ts/tutorials/ex48.c.html
src/tao/tutorials/ex1.c.html
Index of all Sys routines
Table of Contents for all manual pages
Index of all manual pages