address spelling issues

doc/utils/sphinx-config/false_positives.txt

@@ -1012,6 +1012,7 @@ fexternal
 Fexternal
 ffield
 ffl
+fflush
 ffmpeg
 FFmpeg
 ffplay

src/library.cpp

@@ -5442,8 +5442,8 @@ void lammps_fix_external_set_vector(void *handle, const char *id, int idx, doubl
 /** Flush output buffers
 
 \verbatim embed:rst
-This function can be used to force output to be written to screen and logfiles
-to simplify capturing output from LAMMPS library calls.
+This function can be used to flush buffered output to be written to screen
+and logfile pointers to simplify capturing output from LAMMPS library calls.
 \endverbatim
  *
  * \param  handle    pointer to a previously created LAMMPS instance cast to ``void *``.

src/utils.h

@@ -76,8 +76,10 @@ namespace utils {
 
   /*! Flush output buffers
    *
-   *  This function calls fflush on screen and logfile FILE pointers
-   *  if available
+   *  This function calls fflush() on screen and logfile FILE pointers
+   *  if available and thus tells the operating system to output all
+   *  currently buffered data. This is local operation and independent
+   *  from buffering by a file system or an MPI library.
    */
 
   void flush_buffers(LAMMPS *lmp);