Re: _C_IFS_f* functions documentation

[Scott Klement <klemscot@xxxxxxxxxxxx>]

>
> can anyone send me a link to the IBM documentation for the _C_IFS_f* file
> functions?

http://publib.boulder.ibm.com/iseries/v5r2/ic2924/books/c4156071.pdf

>
> the mofocenter search feature seems to be down, and even google can't find
> any reference to these on the ibm site.

Probably because you need to search for fopen() fread() fgets() fclose()
without the _C_IFS_ at the beginning.

You see, there are two fopen() functions.   One works on the
LIBRARY/OBJECT filesystem, and the other works in the IFS.   In C, you use
SYSIFCOPT(*IFSIO) when compiling to specify that it use the IFS versions
of the fopen() API, and SYSIFCOPT(*NOIFSIO) to specify you want the
traditional library/object filesystem.   (or at least, that's my
understanding)

What that really does is substitute a call to _C_IFS_fopen() where you'd
normally have fopen(), and the same for the other functions, fgets(),
fclose(), etc.

In RPG, we have no such compiler keyword, so we create our prototypes to
directly use EXTPROC('_C_IFS_fopen') instead of just EXTPROC('fopen')
(Which I think is actually more elegant than the way the C compiler does
it!!)

But, since those functions were written for C, the documentation about
them refers to fopen() not _C_IFS_fopen().   And the same for the other
functions.