# gphoto2-list.c File Reference

`#include "config.h"`
`#include <gphoto2/gphoto2-list.h>`
`#include <gphoto2/gphoto2-port-log.h>`
`#include <stdio.h>`
`#include <stdlib.h>`
`#include <string.h>`
`#include <gphoto2/gphoto2-result.h>`

## Data Structures

struct | _CameraList

## Defines

#define | CHECK_NULL(r) {if (!(r)) return (GP_ERROR_BAD_PARAMETERS);}
#define | CHECK_RESULT(result) {int r = (result); if (r < 0) return (r);}
#define | CHECK_LIST(list)
#define | CAMERALIST_STRUCT_COMPATIBILITY
#define | MAX_ENTRIES 1024
#define | MAX_LIST_STRING_LENGTH 128
#define | CHECK_INDEX_RANGE(list, index)

## Functions

int | gp_list_new (CameraList **list)
| Creates a new CameraList.
int | gp_list_ref (CameraList *list)
| Increments the reference count of the list.
int | gp_list_unref (CameraList *list)
| Decrements the reference count of the `list`.
int | gp_list_free (CameraList *list)
int | gp_list_reset (CameraList *list)
int | gp_list_append (CameraList *list, const char *name, const char *value)
int | gp_list_sort (CameraList *list)
int | gp_list_count (CameraList *list)
int | gp_list_find_by_name (CameraList *list, int *index, const char *name)
int | gp_list_get_name (CameraList *list, int index, const char **name)
int | gp_list_get_value (CameraList *list, int index, const char **value)
int | gp_list_set_value (CameraList *list, int index, const char *value)
int | gp_list_set_name (CameraList *list, int index, const char *name)
int | gp_list_populate (CameraList *list, const char *format, int count)

## Detailed Description

Author:
  Copyright 2000 Scott Fritzinger

Note:
  This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

## Define Documentation

#define CAMERALIST_STRUCT_COMPATIBILITY

Whether to preserve binary compatibility for structure internals.

Question: Find out whether any libgphoto2 frontend relies on those internals. Answer: They do, at least by instantiation a "struct CameraList foo;".

Binary compatibility and problems: * fixed string size for name and value * fixed max number of entries * some apps instantiate a "struct CameraList foo;" directly and thus reserve a specific amount of memory * FIXME: Do frontends rely on the memory layout and size of their "struct CameraList" or "struct CameraList *" when accessing its members? They *SHOULD* use access functions.

#define CHECK_INDEX_RANGE | ( | list,
|  | index |  | ) |

Value:

    do {                                                    \
        if (index < 0 || index >= list->count) {            \
          return (GP_ERROR_BAD_PARAMETERS);                 \
        }                                                   \
      } while (0)

#define CHECK_LIST | ( | list |  | ) |

Value:

    do {                                                    \
        if (NULL == list) {                                 \
          return (GP_ERROR_BAD_PARAMETERS);                 \
        } else if (list->ref_count == 0) {                  \
          /* catch calls to already freed list */           \
          return (GP_ERROR_BAD_PARAMETERS);                 \
        }                                                   \
      } while (0)

check that the list is valid

#define MAX_ENTRIES 1024

Internal _CameraList data structure

## Function Documentation

int gp_list_append | ( | CameraList * | list,
|  | const char * | name,
|  | const char * | value |
| ) |  |  |

Appends `name` and `value` to the `list`.

Parameters:

  | list | a CameraList
  | name | the name of the entry to append
  | value | the value of the entry to append

Returns:
  a gphoto2 error code

int gp_list_count | ( | CameraList * | list | ) |

Counts the entries in the `list`.

Parameters:

  | list | a CameraList

Returns:
  a gphoto2 error code

int gp_list_find_by_name | ( | CameraList * | list,
|  | int * | index,
|  | const char * | name |
| ) |  |  |

Retrieves the `index` of an arbitrary entry with `name`.

Parameters:

  | list | a CameraList
  | index | pointer to the result index (may be NULL, only set if found)
  | name | name of the entry

Returns:
  a gphoto2 error code: GP_OK if found.

No guarantees as to the speed of the search, or in what sequence the list is searched.

int gp_list_free | ( | CameraList * | list | ) |

Frees the `list`. It is recommended to use gp_list_unref instead.

Parameters:

  | list | the CameraList to be freed

Returns:
  a gphoto2 error code

int gp_list_get_name | ( | CameraList * | list,
|  | int | index,
|  | const char ** | name |
| ) |  |  |

Retrieves the `name` of entry with `index`.

Parameters:

  | list | a CameraList
  | index | index of the entry
  | name |

Returns:
  a gphoto2 error code.

int gp_list_get_value | ( | CameraList * | list,
|  | int | index,
|  | const char ** | value |
| ) |  |  |

Retrieves the value of entry with `index`.

Parameters:

  | list | a CameraList
  | index | index of the entry
  | value |

Returns:
  a gphoto2 error code

int gp_list_new | ( | CameraList ** | list | ) |

Creates a new CameraList.

Parameters:

  | list |

Returns:
  a gphoto2 error code

int gp_list_populate | ( | CameraList * | list,
|  | const char * | format,
|  | int | count |
| ) |  |  |

Adds `count` entries to the list.

Parameters:

  | list | a CameraList
  | format | the format
  | count | number of entries to be added to the list return a gphoto2 error code

Typically, this function is called by a camera driver when there is no way of retrieving the real name of a picture. In this case, when asked for a file list (see CameraFilesystemListFunc), the list is populated with dummy names generated by this function.

int gp_list_ref | ( | CameraList * | list | ) |

Increments the reference count of the list.

Parameters:

  | list | a CameraList

Returns:
  a gphoto2 error code.

int gp_list_reset | ( | CameraList * | list | ) |

Resets the `list` and removes all entries.

Parameters:

  | list | a CameraList

Returns:
  a gphoto2 error code

int gp_list_set_name | ( | CameraList * | list,
|  | int | index,
|  | const char * | name |
| ) |  |  |

Sets the name of an entry.

Parameters:

  | list | a CameraList
  | index | index of entry
  | name | name to be set

Returns:
  a gphoto2 error code

int gp_list_set_value | ( | CameraList * | list,
|  | int | index,
|  | const char * | value |
| ) |  |  |

Sets the `value` of an entry.

Parameters:

  | list | a CameraList
  | index | index of the entry
  | value | the value to be set

Returns:
  a gphoto2 error code

int gp_list_sort | ( | CameraList * | list | ) |

Sorts the `list` entries with respect to the names.

Parameters:

  | list | a CameraList

Returns:
  a gphoto2 error code

int gp_list_unref | ( | CameraList * | list | ) |

Decrements the reference count of the `list`.

Parameters:

  | list | a CameraList

Returns:
  a gphoto2 error code

If there are no references left, the `list` will be freed.