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of C++ I/O may or may not work, and has been seen to crash R.
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of C++ I/O may or may not work, and has been seen to crash R.
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To use F90 or F95, see `Writing R Extensions'.
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To use F90 or F95, see `Writing R Extensions'.
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For other compilers you will need to arrange to produce a DLL with
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For other compilers you will need to arrange to produce a DLL with
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cdecl (also known as _cdecl or __cdecl) linkage.  The mingw port (and
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cdecl (also known as _cdecl or __cdecl) linkage.  The MinGW port (and
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VC++) uses no `name mangling' at all, so that if for example your
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VC++) uses no `name mangling' at all, so that if for example your
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compiler adds leading or trailing underscores you will need to use the
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compiler adds leading or trailing underscores you will need to use the
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transformed symbol in the call to .C in your R code.  Many compilers
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transformed symbol in the call to .C in your R code.  Many compilers
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can produce cdecl DLLs by a suitable choice of flags, but if yours
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can produce cdecl DLLs by a suitable choice of flags, but if yours
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cannot you may need to write some `glue' code in C to interface to the
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cannot you may need to write some `glue' code in C to interface to the
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DLL.
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DLL.
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If you use .Fortran this appends an underscore and does no case
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If you use .Fortran this appends an underscore and does no case
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conversion at all to the symbol name.  It is normally best to use
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conversion at all to the symbol name.  It is normally best to use
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.C with compilers other than g77 and map the name manually if necessary.
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.C with compilers other than gfortran and map the name manually if necessary.
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Care is needed in passing character strings to and from a DLL by .C:
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Care is needed in passing character strings to and from a DLL by .C:
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they must be equivalent to the C type char** and null-terminated.  Not
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they must be equivalent to the C type char** and null-terminated.  Not
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even the mingw g77 Fortran uses null-terminated strings.
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even the MinGW g77 Fortran used null-terminated strings. (g77 was in
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GCC 3.x.y, superseded by gfortran.)
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WARNING: DLLs made with some compilers reset the FPU in their startup
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WARNING: DLLs made with some compilers reset the FPU in their startup
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code (Delphi has been one), and this will cause operations such as
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code (Delphi has been one), and this will cause operations such as
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0./0. to crash R.  You can re-set the FPU to the correct values by a
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0./0. to crash R.  You can re-set the FPU to the correct values by a
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call to the C entry point Rwin_fpset().
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call to the C entry point Rwin_fpset().