Fix bugs #6078 and #9364

[lyx.git] / src / support / environment.cpp

diff --git a/src/support/environment.cpp b/src/support/environment.cpp
index a364725c21173c137c00960c0ba3ea2cc3bb9270..ceaca60f547d86aebc21b295a424b4f08395fb13 100644 (file)
--- a/src/support/environment.cpp
+++ b/src/support/environment.cpp
@@ -28,10 +28,17 @@ using namespace std;
 namespace lyx {
 namespace support {
 
-string const getEnv(string const & envname)
+
+bool hasEnv(string const & name)
+{
+       return getenv(name.c_str());
+}
+
+
+string const getEnv(string const & name)
 {
        // f.ex. what about error checking?
-       char const * const ch = getenv(envname.c_str());
+       char const * const ch = getenv(name.c_str());
        return ch ? to_utf8(from_local8bit(ch)) : string();
 }
 
@@ -64,6 +71,11 @@ bool setEnv(string const & name, string const & value)
 #if defined (HAVE_SETENV)
        return ::setenv(name.c_str(), encoded.c_str(), 1) == 0;
 #elif defined (HAVE_PUTENV)
+       // According to http://pubs.opengroup.org/onlinepubs/9699919799/functions/putenv.html
+       // the argument of putenv() needs to be static, because changing its
+       // value will change the environment. Therefore we need a different static
+       // storage for each variable.
+       // FIXME THREAD
        static map<string, string> varmap;
        varmap[name] = name + '=' + encoded;
        return ::putenv(const_cast<char*>(varmap[name].c_str())) == 0;
@@ -117,5 +129,22 @@ void prependEnvPath(string const & name, string const & prefix)
        setEnvPath(name, env_var);
 }
 
+
+bool unsetEnv(string const & name)
+{
+#if defined(HAVE_UNSETENV)
+       // FIXME: does it leak?
+       return ::unsetenv(name.c_str()) == 0;
+#elif defined(HAVE_PUTENV)
+       // This is OK with MSVC and MinGW at least.
+       // The argument of putenv() does not need to be a static variable in this
+       // case, since the variable is removed from the environment.
+       return ::putenv(const_cast<char*>((name + "=").c_str())) == 0;
+#else
+#error No environment-unsetting function has been defined.
+#endif
+}
+
+
 } // namespace support
 } // namespace lyx