Hi, I observed two different behaviors in gcc 4.8.2 and 4.9 regarding the same issue, IMO both erroneous.
Regarding 4.8.2, #pragma GCC diagnostic ignored "-pedantic" doesn't work in cases such as: void* p = 0; #pragma GCC diagnostic ignored "-pedantic" F* f2 = reinterpret_cast<F*>(p); (see testcase in the patch). The attached patch attempts to fix this issue. Since I no longer have write access, please apply this for me if correct (is the 4.8 branch still alive for adding fixes?). Regarding 4.9, gcc fails to complain at all when -pedantic is passed, even specifying -std=c++03. Please let me know if this is truly a bug, in which case I could also fix it for the latest version as well (if so, please let me know if I should look into trunk or any other branch). Thanks, Daniel. 2014-03-31 Daniel Gutson <daniel.gut...@tallertechnologies.com> gcc/cp/ * typeck.c (build_reinterpret_cast_1): Pass proper argument to warn() in pedantic. gcc/testsuite/g++.dg/ * diagnostic/pedantic.C: New test case.
--- gcc-4.8.2-orig/gcc/cp/typeck.c 2014-03-31 22:29:42.736367936 -0300 +++ gcc-4.8.2/gcc/cp/typeck.c 2014-03-31 14:26:43.536747050 -0300 @@ -6639,7 +6639,7 @@ where possible, and it is necessary in some cases. DR 195 addresses this issue, but as of 2004/10/26 is still in drafting. */ - warning (0, "ISO C++ forbids casting between pointer-to-function and pointer-to-object"); + warning (OPT_Wpedantic, "ISO C++ forbids casting between pointer-to-function and pointer-to-object"); return fold_if_not_in_template (build_nop (type, expr)); } else if (TREE_CODE (type) == VECTOR_TYPE) --- gcc-4.8.2-orig/gcc/testsuite/g++.dg/diagnostic/pedantic.C 1969-12-31 21:00:00.000000000 -0300 +++ gcc-4.8.2/gcc/testsuite/g++.dg/diagnostic/pedantic.C 2014-03-31 17:24:42.532607344 -0300 @@ -0,0 +1,12 @@ +// { dg-do compile } +// { dg-options "-pedantic" } +typedef void F(void); + +void foo() +{ + void* p = 0; + F* f1 = reinterpret_cast<F*>(p); // { dg-warning "ISO" } +#pragma GCC diagnostic ignored "-pedantic" + F* f2 = reinterpret_cast<F*>(p); +} +