asn1_get_length_der - API function

       const unsigned char * der
                   DER data to decode.

       int der_len Length of DER data to decode.

       int * len   Output variable containing the length of the DER length field.

       Copyright © 2006-2025 Free Software Foundation, Inc..
       Copying  and distribution of this file, with or without modification, are permitted in any medium without
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       Extract a length field from DER data.

       asn1_get_length_der - API function

       Return the decoded length value, or -1 on indefinite length, or -2 when the value was too big to fit in a
       int, or -4 when the decoded length value plus  len would exceed  der_len .

       The full documentation for libtasn1 is maintained as a Texinfo manual.  If the info and libtasn1 programs
       are properly installed at your site, the command

              infolibtasn1

       should give you access to the complete manual.  As an alternative you may obtain the manual from:

              https://www.gnu.org/software/libtasn1/manual/

libtasn1                                             4.20.0                               asn1_get_length_der(3)

#include<libtasn1.h>longasn1_get_length_der(constunsignedchar*der,intder_len,int*len);