petsc-3.6.1 2015-08-06

PetscOptionsGetString

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

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

Not Collective

	pre	- string to prepend to name or NULL
	name	- the option one is seeking
	len	- maximum length of the string including null termination

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

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(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

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).