Merge pull request #2746 from Romain-Geissler-1A:master

googletest/include/gtest/internal/gtest-port.h

@@ -252,6 +252,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+
+#include <cerrno>
 #include <cstdint>
 #include <limits>
 #include <type_traits>
@@ -1960,16 +1962,16 @@ namespace posix {
 typedef struct _stat StatStruct;
 
 # ifdef __BORLANDC__
-inline int IsATTY(int fd) { return isatty(fd); }
+inline int DoIsATTY(int fd) { return isatty(fd); }
 inline int StrCaseCmp(const char* s1, const char* s2) {
   return stricmp(s1, s2);
 }
 inline char* StrDup(const char* src) { return strdup(src); }
 # else  // !__BORLANDC__
 #  if GTEST_OS_WINDOWS_MOBILE
-inline int IsATTY(int /* fd */) { return 0; }
+inline int DoIsATTY(int /* fd */) { return 0; }
 #  else
-inline int IsATTY(int fd) { return _isatty(fd); }
+inline int DoIsATTY(int fd) { return _isatty(fd); }
 #  endif  // GTEST_OS_WINDOWS_MOBILE
 inline int StrCaseCmp(const char* s1, const char* s2) {
   return _stricmp(s1, s2);
@@ -1994,7 +1996,7 @@ inline bool IsDir(const StatStruct& st) {
 typedef struct stat StatStruct;
 
 inline int FileNo(FILE* file) { return fileno(file); }
-inline int IsATTY(int fd) { return isatty(fd); }
+inline int DoIsATTY(int fd) { return isatty(fd); }
 inline int Stat(const char* path, StatStruct* buf) {
   // stat function not implemented on ESP8266
   return 0;
@@ -2011,7 +2013,7 @@ inline bool IsDir(const StatStruct& st) { return S_ISDIR(st.st_mode); }
 typedef struct stat StatStruct;
 
 inline int FileNo(FILE* file) { return fileno(file); }
-inline int IsATTY(int fd) { return isatty(fd); }
+inline int DoIsATTY(int fd) { return isatty(fd); }
 inline int Stat(const char* path, StatStruct* buf) { return stat(path, buf); }
 inline int StrCaseCmp(const char* s1, const char* s2) {
   return strcasecmp(s1, s2);
@@ -2022,6 +2024,17 @@ inline bool IsDir(const StatStruct& st) { return S_ISDIR(st.st_mode); }
 
 #endif  // GTEST_OS_WINDOWS
 
+inline int IsATTY(int fd) {
+  // DoIsATTY might change errno (for example ENOTTY in case you redirect stdout
+  // to a file on Linux), which is unexpected, so save the previous value, and
+  // restore it after the call.
+  int savedErrno = errno;
+  int isAttyValue = DoIsATTY(fd);
+  errno = savedErrno;
+
+  return isAttyValue;
+}
+
 // Functions deprecated by MSVC 8.0.
 
 GTEST_DISABLE_MSC_DEPRECATED_PUSH_()