petsc-3.4.2 2013-07-02

# PetscOptionsGetBool

Gets the Logical (true or false) value for a particular option in the database.

### Synopsis

    #include "petscsys.h"
    PetscErrorCode  PetscOptionsGetBool(const char pre[],const char name[],PetscBool  *ivalue,PetscBool  *set)

Not Collective

### Input Parameters

| pre | - the string to prepend to the name or NULL
| name | - the option one is seeking

### Output Parameter

| ivalue | - the logical value to return
| set | - PETSC_TRUE if found, else PETSC_FALSE

### Notes

TRUE, true, YES, yes, nostring, and 1 all translate to PETSC_TRUE FALSE, false, NO, no, and 0 all translate to PETSC_FALSE

If the user does not supply the option (as either true or false) ivalue is NOT changed. Thus you NEED TO ALWAYS initialize the ivalue.

### See Also

PetscOptionsGetReal(), PetscOptionsHasName(), PetscOptionsGetString(),
PetscOptionsGetIntArray(), PetscOptionsGetRealArray(), PetscOptionsGetInt(), PetscOptionsBool(), PetscOptionsName(), PetscOptionsBegin(), PetscOptionsEnd(), PetscOptionsHead(), PetscOptionsStringArray(),PetscOptionsRealArray(), PetscOptionsScalar(), PetscOptionsBoolGroupBegin(), PetscOptionsBoolGroup(), PetscOptionsBoolGroupEnd(), PetscOptionsList(), PetscOptionsEList()

Level:beginner
Location: src/sys/objects/options.c
Index of all Sys routines
Table of Contents for all manual pages
Index of all manual pages

### Examples

src/vec/vec/examples/tutorials/ex10.c.html
src/dm/examples/tutorials/ex1.c.html
src/dm/examples/tutorials/ex2.c.html
src/dm/examples/tutorials/ex5.c.html
src/dm/examples/tutorials/ex12.c.html
src/ksp/ksp/examples/tutorials/ex1.c.html
src/ksp/ksp/examples/tutorials/ex2.c.html
src/ksp/ksp/examples/tutorials/ex4.c.html
src/ksp/ksp/examples/tutorials/ex5.c.html
src/ksp/ksp/examples/tutorials/ex7.c.html
src/ksp/ksp/examples/tutorials/ex8.c.html