xref: /llvm-project/flang/runtime/main.cpp (revision 0ec3ac9b7fbd15698af7289e1214e8ff3d82ec14)
1 //===-- runtime/main.cpp --------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "flang/Runtime/main.h"
10 #include "environment.h"
11 #include "terminator.h"
12 #include <cfenv>
13 #include <cstdio>
14 #include <cstdlib>
15 
ConfigureFloatingPoint()16 static void ConfigureFloatingPoint() {
17 #ifdef feclearexcept // a macro in some environments; omit std::
18   feclearexcept(FE_ALL_EXCEPT);
19 #else
20   std::feclearexcept(FE_ALL_EXCEPT);
21 #endif
22 #ifdef fesetround
23   fesetround(FE_TONEAREST);
24 #else
25   std::fesetround(FE_TONEAREST);
26 #endif
27 }
28 
29 extern "C" {
RTNAME(ProgramStart)30 void RTNAME(ProgramStart)(int argc, const char *argv[], const char *envp[],
31     const EnvironmentDefaultList *envDefaults) {
32   std::atexit(Fortran::runtime::NotifyOtherImagesOfNormalEnd);
33   Fortran::runtime::executionEnvironment.Configure(
34       argc, argv, envp, envDefaults);
35   ConfigureFloatingPoint();
36   // I/O is initialized on demand so that it works for non-Fortran main().
37 }
38 
RTNAME(ByteswapOption)39 void RTNAME(ByteswapOption)() {
40   if (Fortran::runtime::executionEnvironment.conversion ==
41       Fortran::runtime::Convert::Unknown) {
42     // The environment variable overrides the command-line option;
43     // either of them take precedence over explicit OPEN(CONVERT=) specifiers.
44     Fortran::runtime::executionEnvironment.conversion =
45         Fortran::runtime::Convert::Swap;
46   }
47 }
48 }
49