Type "make" to check the validity of the f2c source and compile f2c.

On a PC, you may need to compile xsum.c with -DMSDOS (i.e., with
MSDOS #defined).  If your system does not understand ANSI/ISO C
syntax (i.e., if you have a K&R C compiler), compile xsum.c with
-DKR_headers.  (Eventually this will also be required of the f2c
source proper.)

On non-Unix systems where files have separate binary and text modes,
you may need to "make xsumr.out" rather than "make xsum.out".

If (in accordance with what follows) you need to modify the makefile
or any of the source files, first issue a "make xsum.out" (or, if
appropriate, "make xsumr.out") to check the validity of the f2c source,
then make your changes, then type "make f2c".

The file usignal.h is for the benefit of strictly ANSI include files
on a UNIX system -- the ANSI signal.h does not define SIGHUP or SIGQUIT.
You may need to modify usignal.h if you are not running f2c on a UNIX
system.

Should you get the message "xsum0.out xsum1.out differ", see what lines
are different (`diff xsum0.out xsum1.out`) and ask netlib to send you
the files in question "from f2c/src".  For example, if exec.c and
expr.c have incorrect check sums, you would send netlib the message
	send exec.c expr.c from f2c/src

On some systems, the malloc and free in malloc.c let f2c run faster
than do the standard malloc and free.  Other systems cannot tolerate
redefinition of malloc and free.  If yours is such a system, you may
either modify the makefile appropriately, or simply execute
	cc -c -DCRAY malloc.c
before typing "make".  Still other systems have a -lmalloc that
provides performance competitive with that from malloc.c; you may
wish to compare the two on your system.

On some BSD systems, you may need to create a file named "string.h"
whose single line is
#include <strings.h>
you may need to add " -Dstrchr=index" to the "CFLAGS =" assignment
in the makefile, and you may need to add " memset.o" to the "OBJECTS ="
assignment in the makefile -- see the comments in memset.c .

For non-UNIX systems, you may need to change some things in sysdep.c,
such as the choice of intermediate file names.

On some systems, you may need to modify parts of sysdep.h (which is
included by defs.h).  In particular, for Sun 4.1 systems and perhaps
some others, you need to comment out the typedef of size_t.  For some
systems (e.g., IRIX 4.0.1 and AIX) it is better to add
#define ANSI_Libraries
to the beginning of sysdep.h (or to supply -DANSI_Libraries in the
makefile).

Alas, some systems #define __STDC__ but do not provide a true standard
(ANSI or ISO) C environment, e.g. do not provide stdlib.h .  If yours
is such a system, then (a) you should complain loudly to your vendor
about __STDC__ being erroneously defined, and (b) you should insert
#undef __STDC__
at the beginning of sysdep.h .  You may need to make other adjustments.

For some non-ANSI versions of stdio, you must change the values given
to binread and binwrite in sysdep.c from "rb" and "wb" to "r" and "w".
You may need to make this change if you run f2c and get an error
message of the form
	Compiler error ... cannot open intermediate file ...

On many systems, it is best to combine libF77 and libI77 into a single
library, say libf2c, as suggested in "readme from f2c".  If you do this,
then you should adjust the definition of link_msg in sysdep.c
appropriately (e.g., replacing "-lF77 -lI77" by "-lf2c").

Some older C compilers object to
	typedef void (*foo)();
or to
	typedef void zap;
	zap (*foo)();
If yours is such a compiler, change the definition of VOID in
f2c.h from void to int.

For convenience with systems that use control-Z to denote end-of-file,
f2c treats control-Z characters (ASCII 26, '\x1a') that appear at the
beginning of a line as an end-of-file indicator.  You can disable this
test by compiling lex.c with NO_EOF_CHAR_CHECK #defined, or can
change control-Z to some other character by #defining EOF_CHAR to
be the desired value.

Please send bug reports to dmg@research.att.com .  The old index file
(now called "readme" due to unfortunate changes in netlib conventions:
"send readme from f2c") will report recent changes in the recent-change
log at its end; all changes will be shown in the "changes" file
("send changes from f2c").  To keep current source, you will need to
request xsum0.out and version.c, in addition to the changed source
files.