petsc-3.7.3 2016-07-24
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# PetscOptionsGetString

Gets the string value for a particular option in the database.

### Synopsis

    #include "petscsys.h"
    PetscErrorCode  PetscOptionsGetString(PetscOptions options,const char pre[],const char name[],char string[],size_t len,PetscBool  *set)

Not Collective

### Input Parameters

| options | - options database use NULL for default global database
| pre | - string to prepend to name or NULL
| name | - the option one is seeking
| len | - maximum length of the string including null termination

### Output Parameters

| string | - location to copy string
| set | - PETSC_TRUE if found, else PETSC_FALSE

### Fortran Note

The Fortran interface is slightly different from the C/C++ interface (len is not used). Sample usage in Fortran follows

          character *20 string
          integer   flg, ierr
          call PetscOptionsGetString(PETSC_NULL_OBJECT,PETSC_NULL_CHARACTER,'-s',string,flg,ierr)

Notes: if the option is given but no string is provided then an empty string is returned and set is given the value of PETSC_TRUE

### Note

Even if the user provided no string (for example -optionname -someotheroption) the flag is set to PETSC_TRUE (and the string is fulled with nulls).

### See Also

PetscOptionsGetInt(), PetscOptionsGetReal(),
PetscOptionsHasName(), PetscOptionsGetIntArray(), PetscOptionsGetRealArray(), PetscOptionsBool(), PetscOptionsName(), PetscOptionsBegin(), PetscOptionsEnd(), PetscOptionsHead(), PetscOptionsStringArray(),PetscOptionsRealArray(), PetscOptionsScalar(), PetscOptionsBoolGroupBegin(), PetscOptionsBoolGroup(), PetscOptionsBoolGroupEnd(), PetscOptionsFList(), 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/sys/examples/tutorials/ex5.c.html
src/sys/examples/tutorials/ex9.c.html
src/sys/examples/tutorials/ex10f90.F90.html
src/mat/examples/tutorials/ex1.c.html
src/mat/examples/tutorials/ex4.c.html
src/mat/examples/tutorials/ex5.c.html
src/mat/examples/tutorials/ex9.c.html
src/mat/examples/tutorials/ex10.c.html
src/mat/examples/tutorials/ex12.c.html
src/mat/examples/tutorials/ex16.c.html
src/ksp/ksp/examples/tutorials/ex10.c.html