libssh2/docs/libssh2_session_supported_algs.md

c, SPDX-License-Identifier, Title, Section, Source, See-also

c	SPDX-License-Identifier	Title	Section	Source	See-also
Copyright (C) The libssh2 project and its contributors.	BSD-3-Clause	libssh2_session_supported_algs	3	libssh2	libssh2_free(3) libssh2_session_method_pref(3) libssh2_session_methods(3)

NAME

libssh2_session_supported_algs - get list of supported algorithms

SYNOPSIS

#include <libssh2.h>

int libssh2_session_supported_algs(LIBSSH2_SESSION *session,
                                   int method_type,
                                   const char ***algs);

DESCRIPTION

session - An instance of initialized LIBSSH2_SESSION (the function uses its pointer to the memory allocation function). method_type - Method type. See libssh2_session_method_pref(3). algs - Address of a pointer that points to an array of returned algorithms

Get a list of supported algorithms for the given method_type. The method_type parameter is equivalent to method_type in libssh2_session_method_pref(3). If successful, the function allocates the appropriate amount of memory. When not needed anymore, it must be deallocated by calling libssh2_free(3). When this function is unsuccessful, this must not be done.

In order to get a list of all supported compression algorithms, libssh2_session_flag(session, LIBSSH2_FLAG_COMPRESS, 1) must be called before calling this function, otherwise only "none" is returned.

If successful, the function allocates and fill the array with supported algorithms (the same names as defined in RFC 4253). The array is not NULL terminated.

EXAMPLE

#include "libssh2.h"

const char **algorithms;
int rc, i;
LIBSSH2_SESSION *session;

/* initialize session */
session = libssh2_session_init();
rc = libssh2_session_supported_algs(session,
                                    LIBSSH2_METHOD_CRYPT_CS,
                                    &algorithms);
if(rc > 0) {
    /* the call succeeded, do sth. with the list of algorithms
       (e.g. list them)... */
    printf("Supported symmetric algorithms:\n");
    for(i = 0; i < rc; i++)
        printf("\t%s\n", algorithms[i]);

    /* ... and free the allocated memory when not needed anymore */
    libssh2_free(session, algorithms);
}
else {
    /* call failed, error handling */
}

RETURN VALUE

On success, a number of returned algorithms (i.e a positive number is returned). In case of a failure, an error code (a negative number, see below) is returned. 0 should never be returned.

ERRORS

LIBSSH2_ERROR_BAD_USE - If session or algs are NULL.

LIBSSH2_ERROR_METHOD_NOT_SUPPORTED - Unknown method type.

LIBSSH2_ERROR_INVAL - Internal error (normally should not occur).

LIBSSH2_ERROR_ALLOC - Allocation of memory failed.

AVAILABILITY

Added in 1.4.0