NAME

xo_attr, xo_attr_h, xo_attr_hv — Add attribute name/value pairs to formatted output

LIBRARY

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

SYNOPSIS

#include <libxo/xo.h>

xo_ssize_t
xo_attr(const char *name, const char *fmt, ...);

xo_ssize_t
xo_attr_h(xo_handle_t *handle, const char *name, const char *fmt, ...);

xo_ssize_t
xo_attr_hv(xo_handle_t *handle, const char *name, const char *fmt, va_list vap);

DESCRIPTION

The xo_attr() function emits attributes for the XML output style. The attribute value is recorded in the handle and is attached to the next field that is emitted via a xo_emit(3) call.

The name parameter give the name of the attribute to be encoded. The fmt parameter gives a printf-style format string used to format the value of the attribute using any remaining arguments, or the vap parameter as passed to xo_attr_hv().

    EXAMPLE:
      xo_attr("seconds", "%ld", (unsigned long) login_time);
      struct tm *tmp = localtime(login_time);
      strftime(buf, sizeof(buf), "%R", tmp);
      xo_emit("Logged in at {:login-time}\n", buf);
    XML:
        <login-time seconds="1408336270">00:14</login-time>

Since attributes are only emitted in XML, their use should be limited to meta-data and additional or redundant representations of data already emitted in other form.

SEE ALSO

xo_emit(3), libxo(3)

HISTORY

The libxo library first appeared in FreeBSD 11.0.

AUTHORS

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