http_date.h File Reference

Render a Unix epoch as an RFC 7231 IMF-fixdate. More...

#include <stdint.h>
#include <time.h>
#include "shared_primitives/time_compat.h"

Go to the source code of this file.

Macros
#define	PC_HTTP_DATE_MAX   30
	Smallest buffer that holds an RFC 7231 IMF-fixdate plus its NUL.

Functions
uint8_t	pc_http_date (time_t epoch, char *out, uint32_t out_cap)
	Write epoch into out as an IMF-fixdate in GMT.

Detailed Description

Render a Unix epoch as an RFC 7231 IMF-fixdate.

One formatter serves every header that carries a timestamp (Date, Last-Modified, Expires), so the wire rendering is fixed in one place. The break-down is reentrant (gmtime_r, never the shared static tm), which is what makes it callable from any worker.

Every rejection - no epoch, no buffer, a time that will not break down - returns 0 and leaves out an empty string, so a caller that ignores the length still emits a well-formed header value rather than whatever the buffer held.

Author

Douglas Quigg (dstroy0)

Date

2026

Definition in file http_date.h.

Macro Definition Documentation

PC_HTTP_DATE_MAX

#define PC_HTTP_DATE_MAX   30

Smallest buffer that holds an RFC 7231 IMF-fixdate plus its NUL.

Sun, 06 Nov 1994 08:49:37 GMT is 29 characters and the format is fixed-width, so this is a property of the protocol rather than a tuning choice. A smaller buffer truncates silently, because strftime writes nothing and returns 0 when the result does not fit.

Definition at line 35 of file http_date.h.

Function Documentation

pc_http_date()

uint8_t pc_http_date ( time_t  epoch, char *  out, uint32_t  out_cap  )

inline

Write epoch into out as an IMF-fixdate in GMT.

Returns

characters written, excluding the NUL, or 0 with an empty out on any rejection.

Definition at line 41 of file http_date.h.

References pc_gmtime_r().

Referenced by pc_ntp_http_date(), and pc_time_http_date().