smfi_chgheader

#include <libmilter/mfapi.h>
int smfi_chgheader(
	     SMFICTX *ctx,
	     char *headerf,
	     mi_int32 hdridx,
	     char *headerv
);

smfi_chgheader description

The smfi_chgheader API changes a header's value for the current message. It is called only from xxfi_eom.

ctx: Opaque context structure.
headerf: The header name, a non-NULL, null-terminated string.
hdridx: Header index value (1-based). A hdridx value of 1 modifies the first occurrence of a header named headerf. If hdridx is greater than the number of times headerf appears, a new copy of headerf is added.
headerv: The new value of the given header. A headerv value of NULL implies that the header should be deleted.

smfi_chgheader returns MI_FAILURE in the following cases:

Otherwise, it returns MI_SUCCESS.

Notes:

While smfi_chgheader can be used to add new headers, it is more efficient and safer to use smfi_addheader to add new headers.
A filter that calls smfi_chgheader must have set the SMFIF_CHGHDRS flag in the smfiDesc_str passed to smfi_register.
Filter order is important for smfi_chgheader; later filters see the header changes made by previous filters.
Neither the name nor the value of the header is checked for standards compliance. However, each line of the header must be less than 2048 characters in length and should be less than 998 characters in length. If longer headers are needed, make them multiline. It is the filter writer's responsibility to ensure that no standards are violated.