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Merged
Enchufa2 merged 3 commits into from
Sep 3, 2026
Merged

Avoid -Wcast-function-type warnings #1502

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79969f6
add -Wcast-function-type
Enchufa2 Sep 3, 2026
30fbf33
use intermediate cast to avoid warnings
Enchufa2 Sep 3, 2026
20af051
update Changelog
Enchufa2 Sep 3, 2026
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2 changes: 1 addition & 1 deletion .github/workflows/werror.yml
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Expand Up @@ -8,7 +8,7 @@ on:

env:
_R_CHECK_FORCE_SUGGESTS_: "false"
RCPP_CXXFLAGS: "-Werror"
RCPP_CXXFLAGS: "-Werror -Wcast-function-type"

jobs:
ci:
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14 changes: 14 additions & 0 deletions ChangeLog
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@@ -1,3 +1,17 @@
2026-09-03 Iñaki Ucar <iucar@fedoraproject.org>

* .github/workflows/werror.yaml: Add -Wcast-function-type

* inst/include/Rcpp/routines.h: New function pointer RCPP_FUNC typedef used
as an intermediate cast target to avoid gcc's -Wcast-function-type warnings
* inst/include/Rcpp/Module.h: Idem
* src/rcpp_init.cpp: Idem

* src/attributes.cpp: Generate RCPP_FUNC-routed casts in interface code
* inst/examples/ConvolveBenchmarks/overhead_1.cpp: Update generated code
* inst/tinytest/testRcppInterfaceExporter/src/RcppExports.cpp: Idem
* inst/tinytest/testRcppInterfaceExporter/inst/include/testRcppInterfaceExporter_RcppExports.h: Idem

2026-09-01 Iñaki Ucar <iucar@fedoraproject.org>

* .github/workflows/werror.yaml: Add new CI file with -Werror enabled
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2 changes: 1 addition & 1 deletion inst/examples/ConvolveBenchmarks/overhead_1.cpp
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Expand Up @@ -12,7 +12,7 @@ SEXP overhead_cpp(SEXP a, SEXP b) {
extern "C" void R_init_overhead_1(DllInfo *info){

R_CallMethodDef callMethods[] = {
{"overhead_cpp", (DL_FUNC) &overhead_cpp, 2},
{"overhead_cpp", (DL_FUNC) (RCPP_FUNC) &overhead_cpp, 2},
{NULL, NULL, 0}
};

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2 changes: 1 addition & 1 deletion inst/include/Rcpp/Module.h
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Expand Up @@ -113,7 +113,7 @@ namespace Rcpp {
inline int nargs() { return sizeof...(T); }
inline bool is_void() { return std::is_void<RESULT_TYPE>::value; }
inline void signature(std::string& s, const char* name) { Rcpp::signature<RESULT_TYPE, T...>(s, name); }
inline DL_FUNC get_function_ptr() { return (DL_FUNC)ptr_fun; }
inline DL_FUNC get_function_ptr() { return (DL_FUNC)(RCPP_FUNC)ptr_fun; }

private:
RESULT_TYPE (*ptr_fun)(T...);
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6 changes: 5 additions & 1 deletion inst/include/Rcpp/routines.h
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Expand Up @@ -25,6 +25,10 @@

#include <Rcpp/iostream/Rstreambuf.h>

// Necessary to cast a function pointer to a seemingly incompatible function
// pointer type while avoiding gcc's -Wcast-function-type warnings.
typedef void (*RCPP_FUNC)(void);

#if defined(COMPILING_RCPP)

// the idea is that this file should be generated automatically by Rcpp::register
Expand Down Expand Up @@ -79,7 +83,7 @@ SEXP rcpp_get_current_error();

namespace Rcpp {

#define GET_CALLABLE(__FUN__) (Fun) R_GetCCallable( "Rcpp", __FUN__ )
#define GET_CALLABLE(__FUN__) (Fun) (RCPP_FUNC) R_GetCCallable( "Rcpp", __FUN__ )

inline attribute_hidden const char* type2name(SEXP x){
typedef const char* (*Fun)(SEXP);
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4 changes: 2 additions & 2 deletions inst/tinytest/testRcppInterfaceExporter/inst/include/testRcppInterfaceExporter_RcppExports.h
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Expand Up @@ -15,7 +15,7 @@ namespace testRcppInterfaceExporter {
Rcpp::Function require = Rcpp::Environment::base_env()["require"];
require("testRcppInterfaceExporter", Rcpp::Named("quietly") = true);
typedef int(*Ptr_validate)(const char*);
static Ptr_validate p_validate = (Ptr_validate)
static Ptr_validate p_validate = (Ptr_validate) (RCPP_FUNC)
R_GetCCallable("testRcppInterfaceExporter", "_testRcppInterfaceExporter_RcppExport_validate");
if (!p_validate(sig)) {
throw Rcpp::function_not_exported(
Expand All @@ -29,7 +29,7 @@ namespace testRcppInterfaceExporter {
static Ptr_test_cpp_interface p_test_cpp_interface = NULL;
if (p_test_cpp_interface == NULL) {
validateSignature("SEXP(*test_cpp_interface)(SEXP,bool)");
p_test_cpp_interface = (Ptr_test_cpp_interface)R_GetCCallable("testRcppInterfaceExporter", "_testRcppInterfaceExporter_test_cpp_interface");
p_test_cpp_interface = (Ptr_test_cpp_interface) (RCPP_FUNC)R_GetCCallable("testRcppInterfaceExporter", "_testRcppInterfaceExporter_test_cpp_interface");
}
RObject rcpp_result_gen;
{
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8 changes: 4 additions & 4 deletions inst/tinytest/testRcppInterfaceExporter/src/RcppExports.cpp
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Expand Up @@ -60,14 +60,14 @@ static int _testRcppInterfaceExporter_RcppExport_validate(const char* sig) {

// registerCCallable (register entry points for exported C++ functions)
RcppExport SEXP _testRcppInterfaceExporter_RcppExport_registerCCallable() {
R_RegisterCCallable("testRcppInterfaceExporter", "_testRcppInterfaceExporter_test_cpp_interface", (DL_FUNC)_testRcppInterfaceExporter_test_cpp_interface_try);
R_RegisterCCallable("testRcppInterfaceExporter", "_testRcppInterfaceExporter_RcppExport_validate", (DL_FUNC)_testRcppInterfaceExporter_RcppExport_validate);
R_RegisterCCallable("testRcppInterfaceExporter", "_testRcppInterfaceExporter_test_cpp_interface", (DL_FUNC) (RCPP_FUNC) _testRcppInterfaceExporter_test_cpp_interface_try);
R_RegisterCCallable("testRcppInterfaceExporter", "_testRcppInterfaceExporter_RcppExport_validate", (DL_FUNC) (RCPP_FUNC) _testRcppInterfaceExporter_RcppExport_validate);
return R_NilValue;
}

static const R_CallMethodDef CallEntries[] = {
{"_testRcppInterfaceExporter_test_cpp_interface", (DL_FUNC) &_testRcppInterfaceExporter_test_cpp_interface, 2},
{"_testRcppInterfaceExporter_RcppExport_registerCCallable", (DL_FUNC) &_testRcppInterfaceExporter_RcppExport_registerCCallable, 0},
{"_testRcppInterfaceExporter_test_cpp_interface", (DL_FUNC) (RCPP_FUNC) &_testRcppInterfaceExporter_test_cpp_interface, 2},
{"_testRcppInterfaceExporter_RcppExport_registerCCallable", (DL_FUNC) (RCPP_FUNC) &_testRcppInterfaceExporter_RcppExport_registerCCallable, 0},
{NULL, NULL, 0}
};

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8 changes: 4 additions & 4 deletions src/attributes.cpp
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Expand Up @@ -2103,7 +2103,7 @@ namespace attributes {
ostr() << "static const R_CallMethodDef CallEntries[] = {" << std::endl;
for (std::size_t i=0;i<routineNames.size(); i++) {
ostr() << " {\"" << routineNames[i] << "\", " <<
"(DL_FUNC) &" << routineNames[i] << ", " <<
"(DL_FUNC) (RCPP_FUNC) &" << routineNames[i] << ", " <<
routineArgs[i] << "}," << std::endl;
}
if (callEntries.size() > 0) {
Expand Down Expand Up @@ -2148,7 +2148,7 @@ namespace attributes {
std::string indentStr(indent, ' ');
ostr << indentStr << "R_RegisterCCallable(\"" << package() << "\", "
<< "\"" << packageCppPrefix() << "_" << exportedName << "\", "
<< "(DL_FUNC)" << packageCppPrefix() << "_" << name << ");";
<< "(DL_FUNC) (RCPP_FUNC) " << packageCppPrefix() << "_" << name << ");";
return ostr.str(); // #nocov end
}

Expand Down Expand Up @@ -2221,7 +2221,7 @@ namespace attributes {

std::string ptrName = "p_" + validate;
ostr() << " static " << fnType << " " << ptrName << " = "
<< "(" << fnType << ")" << std::endl
<< "(" << fnType << ") (RCPP_FUNC)" << std::endl
<< " "
<< getCCallable(exportValidationFunctionRegisteredName())
<< ";" << std::endl;
Expand Down Expand Up @@ -2279,7 +2279,7 @@ namespace attributes {
<< "(\"" << function.signature() << "\");"
<< std::endl;
ostr() << " " << ptrName << " = "
<< "(" << fnType << ")"
<< "(" << fnType << ") (RCPP_FUNC)"
<< getCCallable(packageCppPrefix() + "_" + function.name()) << ";"
<< std::endl;
ostr() << " }" << std::endl;
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6 changes: 3 additions & 3 deletions src/rcpp_init.cpp
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Expand Up @@ -25,8 +25,8 @@
#include "internal.h"

// borrowed from Matrix
#define CALLDEF(name, n) {#name, (DL_FUNC) &name, n}
#define EXTDEF(name) {#name, (DL_FUNC) &name, -1}
#define CALLDEF(name, n) {#name, (DL_FUNC) (RCPP_FUNC) &name, n}
#define EXTDEF(name) {#name, (DL_FUNC) (RCPP_FUNC) &name, -1}

static R_CallMethodDef callEntries[] = {
CALLDEF(Class__name,1),
Expand Down Expand Up @@ -89,7 +89,7 @@ void registerFunctions(){
using namespace Rcpp;
using namespace Rcpp::internal;

#define RCPP_REGISTER(__FUN__) R_RegisterCCallable( "Rcpp", #__FUN__ , (DL_FUNC)__FUN__ );
#define RCPP_REGISTER(__FUN__) R_RegisterCCallable( "Rcpp", #__FUN__ , (DL_FUNC) (RCPP_FUNC) __FUN__ );
RCPP_REGISTER(rcpp_get_stack_trace)
RCPP_REGISTER(rcpp_set_stack_trace)
RCPP_REGISTER(type2name)
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