Convenience macro for libssh2_publickey_add_ex(3) calls
#include <libssh2.h>
int libssh2_publickey_add(LIBSSH2_PUBLICKEY *pkey, const unsigned char *name,
const unsigned char *blob, unsigned long blob_len, char overwrite, unsigned long num_attrs, const libssh2_publickey_attribute attrs[]);
This is a macro defined in a public libssh2 header file that is using the underlying function libssh2_publickey_add_ex(3).