.\" zip_file_extra_field_set.mdoc -- set extra field for file in zip
.\" Copyright (C) 2012-2017 Dieter Baron and Thomas Klausner
.\"
.\" This file is part of libzip, a library to manipulate ZIP files.
.\" The authors can be contacted at <libzip@nih.at>
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.Dd December 18, 2017
.Dt ZIP_FILE_EXTRA_FIELD_SET 3
.Os
.Sh NAME
.Nm zip_file_extra_field_set
.Nd set extra field for file in zip
.Sh LIBRARY
libzip (-lzip)
.Sh SYNOPSIS
.In zip.h
.Ft int
.Fn zip_file_extra_field_set "zip_t *archive" "zip_uint64_t index" "zip_uint16_t extra_field_id" "zip_uint16_t extra_field_index" "const zip_uint8_t *extra_field_data" "zip_uint16_t len" "zip_flags_t flags"
.Sh DESCRIPTION
The
.Fn zip_file_extra_field_set
function sets the extra field with ID (two-byte signature)
.Ar extra_field_id
and index
.Ar extra_field_index
for the file at position
.Ar index
in the zip archive.
The extra field's data will be set to
.Ar extra_field_data
and length
.Ar len .
If a new entry shall be appended, set
.Ar extra_field_index
to
.Dv ZIP_EXTRA_FIELD_NEW .
.Pp
At least one of the following
.Ar flags
must be set:
.Bl -tag -width ZIP_FL_CENTRALXX -offset indent
.It Dv ZIP_FL_CENTRAL
Set extra field in the archive's central directory.
.It Dv ZIP_FL_LOCAL
Set extra field in the local file headers.
.El
.Pp
Please note that the extra field IDs 0x0001 (ZIP64 extension),
0x6375 (Infozip UTF-8 comment), and
0x7075 (Infozip UTF-8 file name) can not be set using
.Fn zip_file_extra_field_set
since they are set by
.Xr libzip 3
automatically when needed.
.Sh RETURN VALUES
Upon successful completion 0 is returned.
Otherwise, \-1 is returned and the error code in
.Ar archive
is set to indicate the error.
.Sh ERRORS
.Fn zip_file_extra_field_set
fails if:
.Bl -tag -width Er
.It Bq Er ZIP_ER_INVAL
The extra field size is too large (ID and length need 4 bytes; the
maximum length of all extra fields for one file combined is 65536
bytes).
This error also occurs if
.Ar extra_field_index
is too large.
.It Bq Er ZIP_ER_MEMORY
Required memory could not be allocated.
.It Bq Er ZIP_ER_NOENT
.Ar index
is not a valid file index in
.Ar archive .
.El
.Sh SEE ALSO
.Xr libzip 3 ,
.Xr zip_file_extra_field_delete 3 ,
.Xr zip_file_extra_field_get 3 ,
.Xr zip_file_extra_fields_count 3
.Sh HISTORY
.Fn zip_file_extra_field_set
was added in libzip 0.11.
.Sh AUTHORS
.An -nosplit
.An Dieter Baron Aq Mt dillo@nih.at
and
.An Thomas Klausner Aq Mt tk@giga.or.at