SECP256K1_SCHNORRSIG_EXTRAPARAMS_INIT does not work with C++ #962

1. 
   guidovranken commented at 3:05 pm on July 3, 2021: none

   0#include <secp256k1.h>
   1#include <secp256k1_schnorrsig.h>
   2
   3int main(void)
   4{
   5    secp256k1_schnorrsig_extraparams extraparams = SECP256K1_SCHNORRSIG_EXTRAPARAMS_INIT;
   6    return 0;
   7}
   

   This compiles as C but not as C++.

   clang++:

   0x.cpp:6:52: error: initializer-string for char array is too long
   1    secp256k1_schnorrsig_extraparams extraparams = SECP256K1_SCHNORRSIG_EXTRAPARAMS_INIT;
   2                                                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   3/secp256k1/include/secp256k1_schnorrsig.h:90:5: note: expanded from macro 'SECP256K1_SCHNORRSIG_EXTRAPARAMS_INIT'
   4    SECP256K1_SCHNORRSIG_EXTRAPARAMS_MAGIC,\
   5    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   6/secp256k1/include/secp256k1_schnorrsig.h:88:48: note: expanded from macro 'SECP256K1_SCHNORRSIG_EXTRAPARAMS_MAGIC'
   7#define SECP256K1_SCHNORRSIG_EXTRAPARAMS_MAGIC "\xda\x6f\xb3\x8c"
   8                                               ^~~~~~~~~~~~~~~~~~
   91 error generated.
   

   g++

   0In file included from x.cpp:2:0:
   1x.cpp: In function ‘int main()’:
   2/secp256k1/include/secp256k1_schnorrsig.h:93:1: error: initializer-string for array of chars is too long [-fpermissive]
   3 }
   4 ^
   5x.cpp:6:52: note: in expansion of macro ‘SECP256K1_SCHNORRSIG_EXTRAPARAMS_INIT’
   6     secp256k1_schnorrsig_extraparams extraparams = SECP256K1_SCHNORRSIG_EXTRAPARAMS_INIT;
   

2. 
   real-or-random commented at 8:18 pm on July 3, 2021: contributor

   I guess there’s an unwritten rule that the include files should work in C++ too… Maybe we should test this in CI.

   Here’s a related CI failure after merging the same PR #844 (when CI was running on the PR, we didn’t have -Werror yet…), which doesn’t deserve an issue on its own: https://github.com/bitcoin-core/secp256k1/runs/2978402299

   cc @jonasnick

3. real-or-random referenced this in commit 792d7c4666 on Jul 4, 2021
4. real-or-random cross-referenced this on Jul 4, 2021 from issue "Schnorrsig API overhaul" fixups by real-or-random
5. real-or-random referenced this in commit 769528f307 on Jul 5, 2021
6. jonasnick closed this on Jul 5, 2021

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7. dderjoel referenced this in commit 75a8292f2a on May 23, 2023

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