Introduction to the libVOTable library

The VOTable Library consists in a single header file votable.h providing a set of C functions that can be used in your own sources, to manage memory, parse document. It is portable , efficient and simple to use.

Library structure

The file votable.h contains all the functions that compose the library itself. It is organized as follows :

Define indicating the value returned by the library.

  #define RETURN_OK 0
  #define RETURN_ERROR 1
  #define EXIT_MEMORY 2
  #define EXIT_READING 3

All functions for memory managing
All functions to extract attributes and values in VOTable format

To use this library in your own C code, include the following line :

  #include "votable.h"

How to parse a VOTable file with the libVOTable

To parse a VOTable file with the libVOTable, follow the instructions :

First, initialise memory and structures with Init_VO_Parser function.
Then use Extract_VO_Fields to load in memory all attributes of each FIELD elements. Browse memory with a pointer and write the returned FIELD position in a array. This array contains all data positions that you want to extract in TABLEDATA element.
Once it is filled, the array can be provided as a parameter to Extract_VO_TableData function, that it will return the data back
If you want go on to parse (if it is possible) or jump a part of the file, you can do so the Move_to_Next_VO_Fields and Move_to_Next_VO_Table functions
When you are at the end with the VOTable parser, don't forget to free memory ;-)

To easier the functions usage, they have been grouped together into modules in the documentation. These modules are :

Initialization and memory management
Extract Attributes and values from a VOTABLE element
Jump to a VOTABLE tag

How to compile ?

Thanks to its packaging, the libVOTable library is a very light and user-friendly library . The easiest way to compile your own code test.c with the libVOTable library is to type :

  libtool gcc -o test -static test.c libvotable.la -I/usr/local/include/libxml2 -lxml2

What's next ?

If you are ready to get more, and to start writing more serious programs with libVOTable, you are invited to go to the Tutorial : Getting Started section.