.\" DO NOT MODIFY THIS FILE!  It was generated by gdoc.
.TH "shishi_asn1_read_optional" 3 "1.0.3" "shishi" "shishi"
.SH NAME
shishi_asn1_read_optional \- API function
.SH SYNOPSIS
.B #include <shishi.h>
.sp
.BI "int shishi_asn1_read_optional(Shishi * " handle ", Shishi_asn1 " node ", const char * " field ", char ** " data ", size_t * " datalen ");"
.SH ARGUMENTS
.IP "Shishi * handle" 12
shishi handle as allocated by \fBshishi_init()\fP.
.IP "Shishi_asn1 node" 12
ASN.1 variable to read field from.
.IP "const char * field" 12
name of field in \fInode\fP to read.
.IP "char ** data" 12
newly allocated output buffer that will hold ASN.1 field data.
.IP "size_t * datalen" 12
actual size of output buffer.
.SH "DESCRIPTION"
Extract data stored in a ASN.1 field into a newly allocated buffer.
If the field does not exist (i.e., SHISHI_ASN1_NO_ELEMENT), this
function set datalen to 0 and succeeds.  Can be useful to read
ASN.1 fields which are marked OPTIONAL in the grammar, if you want
to avoid special error handling in your code.
.SH "RETURN VALUE"
Returns SHISHI_OK if successful,
SHISHI_ASN1_NO_VALUE if the field has no value, ot
SHISHI_ASN1_ERROR otherwise.
.SH "REPORTING BUGS"
Report bugs to <bug-shishi@gnu.org>.
GNU Shishi home page: http://www.gnu.org/software/shishi/
General help using GNU software: http://www.gnu.org/gethelp/
.SH COPYRIGHT
Copyright \(co 2002-2022 Simon Josefsson.
.br
Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved.
.SH "SEE ALSO"
The full documentation for
.B shishi
is maintained as a Texinfo manual.  If the
.B info
and
.B shishi
programs are properly installed at your site, the command
.IP
.B info shishi
.PP
should give you access to the complete manual.