914276e4d2
This fixes a build issue with MSVC. While MSVC imports *functions* from DLLs automatically when building a consumer of the DLL, it does not import *variables* automatically. In these cases, we need an explicit __declspec(dllimport). This commit simply changes our logic to what the libtool manual suggests, which has a very comprehensive writeup on the topic. Note that in particular, this solution is carefully designed not to break static linking. However, as described in the libtool manual, statically linking the library with MSVC will output warning LNK4217. This is still the best solution overall, because the warning is merely a cosmetic issue.
64 lines
2.5 KiB
C
64 lines
2.5 KiB
C
#ifndef SECP256K1_ECDH_H
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#define SECP256K1_ECDH_H
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#include "secp256k1.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/** A pointer to a function that hashes an EC point to obtain an ECDH secret
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*
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* Returns: 1 if the point was successfully hashed.
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* 0 will cause secp256k1_ecdh to fail and return 0.
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* Other return values are not allowed, and the behaviour of
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* secp256k1_ecdh is undefined for other return values.
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* Out: output: pointer to an array to be filled by the function
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* In: x32: pointer to a 32-byte x coordinate
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* y32: pointer to a 32-byte y coordinate
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* data: arbitrary data pointer that is passed through
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*/
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typedef int (*secp256k1_ecdh_hash_function)(
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unsigned char *output,
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const unsigned char *x32,
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const unsigned char *y32,
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void *data
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);
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/** An implementation of SHA256 hash function that applies to compressed public key.
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* Populates the output parameter with 32 bytes. */
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SECP256K1_API_VAR const secp256k1_ecdh_hash_function secp256k1_ecdh_hash_function_sha256;
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/** A default ECDH hash function (currently equal to secp256k1_ecdh_hash_function_sha256).
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* Populates the output parameter with 32 bytes. */
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SECP256K1_API_VAR const secp256k1_ecdh_hash_function secp256k1_ecdh_hash_function_default;
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/** Compute an EC Diffie-Hellman secret in constant time
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*
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* Returns: 1: exponentiation was successful
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* 0: scalar was invalid (zero or overflow) or hashfp returned 0
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* Args: ctx: pointer to a context object.
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* Out: output: pointer to an array to be filled by hashfp.
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* In: pubkey: a pointer to a secp256k1_pubkey containing an initialized public key.
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* seckey: a 32-byte scalar with which to multiply the point.
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* hashfp: pointer to a hash function. If NULL,
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* secp256k1_ecdh_hash_function_sha256 is used
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* (in which case, 32 bytes will be written to output).
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* data: arbitrary data pointer that is passed through to hashfp
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* (can be NULL for secp256k1_ecdh_hash_function_sha256).
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*/
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SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdh(
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const secp256k1_context* ctx,
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unsigned char *output,
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const secp256k1_pubkey *pubkey,
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const unsigned char *seckey,
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secp256k1_ecdh_hash_function hashfp,
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void *data
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) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
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#ifdef __cplusplus
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}
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#endif
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#endif /* SECP256K1_ECDH_H */
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