Add an ExecuteNoWait interface to support asynchronous process spawning.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75055 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/System/Program.h

@@ -87,6 +87,43 @@ namespace sys {
       static bool ChangeStdinToBinary();
       static bool ChangeStdoutToBinary();
     /// @}
+
+     /// This function executes the program using the \p arguments provided and
+     /// waits for the program to exit. This function will block the current
+     /// program until the invoked program exits. The invoked program will
+     /// inherit the stdin, stdout, and stderr file descriptors, the
+     /// environment and other configuration settings of the invoking program.
+     /// If Path::executable() does not return true when this function is
+     /// called then a std::string is thrown.
+     /// @returns an integer result code indicating the status of the program.
+     /// A zero or positive value indicates the result code of the program. A
+     /// negative value is the signal number on which it terminated. 
+     /// @see FindProgrambyName
+     /// @brief Executes the program with the given set of \p args.
+     static void ExecuteNoWait(
+        const Path& path,  ///< sys::Path object providing the path of the 
+        ///< program to be executed. It is presumed this is the result of 
+        ///< the FindProgramByName method.
+        const char** args, ///< A vector of strings that are passed to the
+        ///< program.  The first element should be the name of the program.
+        ///< The list *must* be terminated by a null char* entry.
+        const char ** env = 0, ///< An optional vector of strings to use for
+        ///< the program's environment. If not provided, the current program's
+        ///< environment will be used.
+        const sys::Path** redirects = 0, ///< An optional array of pointers to
+        ///< Paths. If the array is null, no redirection is done. The array
+        ///< should have a size of at least three. If the pointer in the array
+        ///< are not null, then the inferior process's stdin(0), stdout(1),
+        ///< and stderr(2) will be redirected to the corresponding Paths.
+        unsigned memoryLimit = 0, ///< If non-zero, this specifies max. amount
+        ///< of memory can be allocated by process. If memory usage will be
+        ///< higher limit, the child is killed and this call returns. If zero -
+        ///< no memory limit.
+        std::string* ErrMsg = 0 ///< If non-zero, provides a pointer to a string
+        ///< instance in which error messages will be returned. If the string 
+        ///< is non-empty upon return an error occurred while invoking the
+        ///< program.
+        );
   };
 }
 }