xo_set_info - Man Page

set the field information data for libxo


Text, XML, JSON, and HTML Output Emission Library (libxo, -lxo)


#include <libxo/xo.h>

xo_set_info(xo_handle_t *handle, xo_info_t *info, int count);


HTML data can include additional information in attributes that begin with "data-". To enable this, three things must occur:

First the application must build an array of xo_info_t structures, one per tag. The array must be sorted by name, since libxo uses a binary search to find the entry that matches names from format instructions.

The xo_info_t structure is defined in <libxo/xo.h>:

    typedef struct xo_info_s {
        const char *xi_name;    /* Name of the element */
        const char *xi_type;    /* Type of field */
        const char *xi_help;    /* Description of field */
    } xo_info_t;

Second, the application must inform libxo about this information using the xo_set_info() call. Like other libxo calls, passing NULL for the handle tells libxo to use the default handle.

If the count is -1, libxo will count the elements of info, but there must be an empty element at the end. More typically, the number is known to the application:

    xo_info_t info[] = {
        { "in-stock", "number", "Number of items in stock" },
        { "name", "string", "Name of the item" },
        { "on-order", "number", "Number of items on order" },
        { "sku", "string", "Stock Keeping Unit" },
        { "sold", "number", "Number of items sold" },
    int info_count = (sizeof(info) / sizeof(info[0]));
    xo_set_info(NULL, info, info_count);

Third, the emission of info must be triggered with the XOF_INFO flag using either the xo_set_flags() function or the “--libxo=info” command line argument.

The type and help values, if present, are emitted as the "data-type" and "data-help" attributes:

  <div class="data" data-tag="sku" data-type="string"
       data-help="Stock Keeping Unit">GRO-000-533</div>

See Also

xo_emit(3), libxo(3)


The libxo library first appeared in FreeBSD 11.0.


libxo was written by Phil Shafer <phil@freebsd.org>.

Additional Documentation

FreeBSD uses libxo version 1.6.0. Complete documentation can be found on github:


libxo lives on github as:


The latest release of libxo is available at:



The libxo library was added in FreeBSD 11.0.


Phil Shafer

Referenced By

libxo(3), xo_set_flags(3).

December 4, 2014