KJSON_PUTNULL(3) Library Functions Manual KJSON_PUTNULL(3)

kjson_putnull, kjson_putnullp
put null content for kcgijson

library “libkcgijson”

#include <sys/types.h>
#include <stdarg.h>
#include <stdint.h>
#include <kcgi.h>
#include <kcgijson.h>

enum kcgi_err
kjson_putnull(struct kjsonreq *req);

enum kcgi_err
kjson_putnullp(struct kjsonreq *req, const char *name);

Write a null to a context req initialised with khtml_open(3).

The kjson_putnull() form is for array scopes and kjson_putnullp() for objects.

Passing a NULL value to name for kjson_putnullp(), is equivalent to calling kjson_putnull().

Returns an enum kcgi_err indicating the error state.
Success (not an error).
Internal memory allocation failure.
The output connection has been terminated. For FastCGI connections, the current connection should be released with khttp_free(3) and parse loop reentered.
The connection is still expecting headers with khttp_head(3). Indicates that khttp_body(3) did not return with success or was not invoked. For FastCGI connections, the current connection should be released with khttp_free(3) and parse loop reentered.
Internal system error writing to the output stream.
The incorrect form was used for the current scope, for example, an array-type write within an object.

The following outputs a simple JSON document. It assumes r is a struct kreq pointer. For brevity, it does not do any error checking.
khttp_head(r, kresps[KRESP_STATUS],
  "%s", khttps[KHTTP_200]);
khttp_head(r, kresps[KRESP_CONTENT_TYPE],
  "%s", kmimetypes[KMIME_APP_JSON]);
khttp_body(r);
kjson_open(&req, r);
kjson_obj_open(&req);
kjson_putnullp(&req, "bar");
kjson_close(&req);

kcgijson(3)

Written by Kristaps Dzonsons <kristaps@bsd.lv>.
March 27, 2020 OpenBSD 6.5