ftell (GNU Gnulib)

Gnulib module: ftell

Portability problems fixed by Gnulib:

This function mistakenly succeeds on pipes on some platforms: mingw, MSVC 14.
This function produces incorrect results after putc that followed a getc call that reached EOF on some platforms: Solaris 11 2010-11.
This function, when invoked after ungetc, throws away the ungetc buffer, changes the stream’s file position, and returns the wrong position on some platforms: macOS 10.15, 11, 12.
This function mistakenly succeeds on pipes on some platforms: mingw 10.

Portability problems not fixed by Gnulib:

This function produces incorrect results immediately after fseek on some platforms: HP-UX 11.
fflush, ftell, ftello, fgetpos behave incorrectly on input streams that are opened in O_TEXT mode and whose contents contains Unix line terminators (LF), on some platforms: mingw, MSVC 14.
On platforms where long is a 32-bit type, ftell does not work correctly with files 2 GiB and larger, even when the AC_SYS_LARGEFILE macro is used. The fix is to use ftello instead.