setvbuf
=======

POSIX specification:
 https://pubs.opengroup.org/onlinepubs/9699919799/functions/setvbuf.html

Gnulib module: ---

Portability problems fixed by Gnulib:

Portability problems not fixed by Gnulib:

  * On Windows platforms (excluding Cygwin), this function does not set errno upon failure.

  * On Windows platforms (excluding Cygwin), _IOLBF (line-buffering) is treated as if it were _IOFBF (full buffering), possibly with a warning generated.