As the FSF advises, 'There is no legal significance to using the
three-character sequence “(C)”, but it does no harm.' It does take up
space though! For that reason, we remove it here from our C files.
Reported at <https://bugs.gnu.org/28784>.
Discussed at
<https://lists.gnu.org/archive/html/guile-devel/2017-10/msg00003.html>.
* libguile/fports.c (revealed_ports, revealed_lock): Remove.
(scm_revealed_count): Just return 'SCM_REVEALED (port)'.
(scm_set_port_revealed_x, scm_adjust_port_revealed_x): Remove
REVEALED_PORTS manipulation.
(fport_close): Do nothing when SCM_REVEALED (port) > 0.
* libguile/fports.h (scm_t_fport): Adjust comment; make 'revealed'
unsigned.
* libguile/ports.c (do_close): Call 'close_port' instead of
'scm_close_port'.
(scm_close_port): Rename to...
(close_port): ... this. Add 'explicit' parameter. Clear 'revealed'
field when PORT is a file port and EXPLICIT is true.
(scm_close_port): Call 'close_port'.
* test-suite/tests/ports.test ("close-port & revealed port")
("revealed port fdes not closed"): New tests.
* m4/mkstemp.m4: Remove.
* lib/mkstemp.c: Remove.
* lib/mkostemp.c: New file.
* m4/mkostemp.m4: New file.
* lib/Makefile.am:
* m4/gnulib-cache.m4:
* m4/gnulib-comp.m4: Remove mkstemp module, replace with mkostemp.
* libguile/fports.h:
* libguile/fports.c (scm_i_mode_to_open_flags): Factor out helper to
parse mode string to open flags.
(scm_open_file_with_encoding): Use the new helper.
* libguile/filesys.c:
(scm_i_mkstemp): Adapt to take optional second argument, being a mode
string. Use mkostemp.
(scm_mkstemp): Backwards compatible shim that calls scm_i_mkstemp.
* doc/ref/posix.texi:
* NEWS: Update.
* module/system/base/compile.scm (call-with-output-file/atomic): Pass
"wb" as mode, to cause O_BINARY to be added on MinGW.
This removes a limitation on the number of port types, simplifies the
API, and removes a central point of coordination.
* libguile/ports-internal.h (struct scm_t_port_type): Rename from
scm_t_ptob_descriptor, now that it's private. Add GOOPS class
fields.
(struct scm_t_port): Rename from struct scm_port, especially
considering that deprecated.h redefines scm_port using the
preprocessor :(.
* libguile/ports.h: Add definitions of SCM_PORT and SCM_PORT_TYPE,
though the scm_t_port and scm_t_port_type types are incomplete.
(SCM_TC2PTOBNUM, SCM_PTOBNUM, SCM_PTOBNAME): Remove, as there are no
more typecodes for port types.
(scm_c_num_port_types, scm_c_port_type_ref, scm_c_port_type_add_x):
Remove.
(scm_make_port_type): Return a scm_t_port_type*. All methods adapted
to take a scm_t_port_type* instead of a ptobnum.
(scm_c_make_port_with_encoding, scm_c_make_port): Take a port type
pointer instead of a tag.
(scm_new_port_table_entry): Remove; not useful.
* libguile/ports.c: Remove things related to the port kind table. Adapt
uses of SCM_PORT_DESCRIPTOR / scm_t_ptob_descriptor to use
SCM_PORT_TYPE and scm_t_port_type.
* libguile/deprecated.c:
* libguile/deprecated.h:
* libguile/filesys.c:
* libguile/fports.c:
* libguile/fports.h:
* libguile/print.c:
* libguile/r6rs-ports.c:
* libguile/strports.c:
* libguile/strports.h:
* libguile/tags.h:
* libguile/vports.c:
* test-suite/standalone/test-scm-c-read.c: Adapt to change.
* libguile/goops.c (scm_class_of, make_port_classes)
(scm_make_port_classes, create_port_classes): Adapt to store the
classes in the ptob.
* libguile/fports.c (scm_open_file_with_encoding): New API function,
containing the code previously found in 'scm_open_file', but modified
to accept the new 'guess_encoding' and 'encoding' arguments.
(scm_open_file): Now just a simple wrapper that calls
'scm_open_file_with_encoding'.
(scm_i_open_file): New implementation of 'open-file' that accepts
keyword arguments '#:guess-encoding' and '#:encoding', and calls
'scm_open_file_with_encoding'.
(scm_init_fports_keywords): New initialization function that gets
called after keywords are initialized.
* libguile/fports.h (scm_open_file_with_encoding,
scm_init_fports_keywords): Add prototypes.
* libguile/init.c (scm_i_init_guile): Call 'scm_init_fports_keywords'.
* module/ice-9/boot-9.scm: Add enhanced versions of 'open-input-file',
'open-output-file', 'call-with-input-file', 'call-with-output-file',
'with-input-from-file', 'with-output-to-file', and
'with-error-to-file', that accept keyword arguments '#:binary',
'#:encoding', and (for input port constructors) '#:guess-encoding'.
* doc/ref/api-io.texi (File Ports): Update documentation.
* test-suite/tests/ports.test ("keyword arguments for file openers"):
Add tests.
* libguile/fports.c (scm_revealed_count, scm_port_revealed)
(scm_set_port_revealed_x, scm_adjust_port_revealed_x): Move these APIs
here, and only operate on fports. To keep revealed ports alive, now
we will just keep them in a data structure that the GC knows about --
a static list.
* libguile/fports.h: Add revealed count to scm_t_fport, and move decls
of revealed-count functions here.
* libguile/ports.h:
* libguile/ports.c: Adapt to change. Remove SCM_REVEALED and
SCM_SETREVEALED; since they only apply to fports now, keeping them
around would be inviting type errors.
(finalize_port): We don't need to worry about resuscitating ports
here.
* libguile/init.c: Use the scm_set_port_revealed_x function to set the
revealed counts on stream ports.
scm_fdes_to_port, but take mode bits directly instead of as a C
string.
(scm_i_fdes_to_port): Implement using above.
(scm_open_file): Use scm_i_fdes_to_port together with
scm_i_mode_bits to avoid accessing internals of SCM string from C.
* vports.c (scm_make_soft_port): Use scm_i_fdes_to_port together
with scm_i_mode_bits to avoid accessing internals of SCM string
from C.
* ports.h (scm_i_mode_bits): New, same as scm_mode_bits but with a
SCM string as argument.
* ports.c (scm_i_void_port): New, like scm_void_port but take mode
bits directly instead of C string.
(scm_void_port): Implement using above.
(scm_sys_make_void_port): Use scm_i_void_port together with
scm_i_mode_bits to avoid accessing internals of SCM string.
* convert.i.c, backtrace.c, strop.c, strorder.c, strports.c,
struct.c, unif.c, ports.c: Use SCM_I_STRING_CHARS,
SCM_I_STRING_UCHARS, and SCM_I_STRING_LENGTH instead of
SCM_STRING_CHARS, SCM_STRING_UCHARS, and SCM_STRING_LENGTH,
respectively. Also, replaced scm_return_first with more explicit
scm_remember_upto_here_1, etc, or introduced them in the first
place.
(SCM_NUM2{SIZE,PTRDIFF,SHORT,USHORT,BITS,UBITS,INT,UINT}[_DEF]):
new macros.
* unif.h: type renaming:
scm_array -> scm_array_t
scm_array_dim -> scm_array_dim_t
the old names are deprecated, all in-Guile uses changed.
* tags.h (scm_ubits_t): new typedef, representing unsigned
scm_bits_t.
* stacks.h: type renaming:
scm_info_frame -> scm_info_frame_t
scm_stack -> scm_stack_t
the old names are deprecated, all in-Guile uses changed.
* srcprop.h: type renaming:
scm_srcprops -> scm_srcprops_t
scm_srcprops_chunk -> scm_srcprops_chunk_t
the old names are deprecated, all in-Guile uses changed.
* gsubr.c, procs.c, print.c, ports.c, read.c, rdelim.c, ramap.c,
rw.c, smob.c, sort.c, srcprop.c, stacks.c, strings.c, strop.c,
strorder.c, strports.c, struct.c, symbols.c, unif.c, values.c,
vectors.c, vports.c, weaks.c:
various int/size_t -> size_t/scm_bits_t changes.
* random.h: type renaming:
scm_rstate -> scm_rstate_t
scm_rng -> scm_rng_t
scm_i_rstate -> scm_i_rstate_t
the old names are deprecated, all in-Guile uses changed.
* procs.h: type renaming:
scm_subr_entry -> scm_subr_entry_t
the old name is deprecated, all in-Guile uses changed.
* options.h (scm_option_t.val): unsigned long -> scm_bits_t.
type renaming:
scm_option -> scm_option_t
the old name is deprecated, all in-Guile uses changed.
* objects.c: various long -> scm_bits_t changes.
(scm_i_make_class_object): flags: unsigned long -> scm_ubits_t
* numbers.h (SCM_FIXNUM_BIT): deprecated, renamed to
SCM_I_FIXNUM_BIT.
* num2integral.i.c: new file, multiply included by numbers.c, used
to "templatize" the various integral <-> num conversion routines.
* numbers.c (scm_mkbig, scm_big2num, scm_adjbig, scm_normbig,
scm_copybig, scm_2ulong2big, scm_dbl2big, scm_big2dbl):
deprecated.
(scm_i_mkbig, scm_i_big2inum, scm_i_adjbig, scm_i_normbig,
scm_i_copybig, scm_i_short2big, scm_i_ushort2big, scm_i_int2big,
scm_i_uint2big, scm_i_long2big, scm_i_ulong2big, scm_i_bits2big,
scm_i_ubits2big, scm_i_size2big, scm_i_ptrdiff2big,
scm_i_long_long2big, scm_i_ulong_long2big, scm_i_dbl2big,
scm_i_big2dbl, scm_short2num, scm_ushort2num, scm_int2num,
scm_uint2num, scm_bits2num, scm_ubits2num, scm_size2num,
scm_ptrdiff2num, scm_num2short, scm_num2ushort, scm_num2int,
scm_num2uint, scm_num2bits, scm_num2ubits, scm_num2ptrdiff,
scm_num2size): new functions.
* modules.c (scm_module_reverse_lookup): i, n: int -> scm_bits_t.x
* load.c: change int -> size_t in various places (where the
variable is used to store a string length).
(search-path): call scm_done_free, not scm_done_malloc.
* list.c (scm_ilength): return a scm_bits_t, not long.
some other {int,long} -> scm_bits_t changes.
* hashtab.c: various [u]int -> scm_bits_t changes.
scm_ihashx_closure -> scm_ihashx_closure_t (and made a typedef).
(scm_ihashx): n: uint -> scm_bits_t
use scm_bits2num instead of scm_ulong2num.
* gsubr.c: various int -> scm_bits_t changes.
* gh_data.c (gh_scm2double): no loss of precision any more.
* gh.h (gh_str2scm): len: int -> size_t
(gh_{get,set}_substr): start: int -> scm_bits_t,
len: int -> size_t
(gh_<num>2scm): n: int -> scm_bits_t
(gh_*vector_length): return scm_[u]size_t, not unsigned long.
(gh_length): return scm_bits_t, not unsigned long.
* fports.h: type renaming:
scm_fport -> scm_fport_t
the old name is deprecated, all in-Guile uses changed.
* fports.c (fport_fill_input): count: int -> scm_bits_t
(fport_flush): init_size, remaining, count: int -> scm_bits_t
* debug.h (scm_lookup_cstr, scm_lookup_soft, scm_evstr): removed
those prototypes, as the functions they prototype don't exist.
* fports.c (default_buffer_size): int -> size_t
(scm_fport_buffer_add): read_size, write_size: int -> scm_bits_t
default_size: int -> size_t
(scm_setvbuf): csize: int -> scm_bits_t
* fluids.c (n_fluids): int -> scm_bits_t
(grow_fluids): old_length, i: int -> scm_bits_t
(next_fluid_num, scm_fluid_ref, scm_fluid_set_x): n: int ->
scm_bits_t
(scm_c_with_fluids): flen, vlen: int -> scm_bits_t
* filesys.c (s_scm_open_fdes): changed calls to SCM_NUM2LONG to
the new and shiny SCM_NUM2INT.
* extensions.c: extension -> extension_t (and made a typedef).
* eval.h (SCM_IFRAME): cast to scm_bits_t, not int. just so
there are no nasty surprises if/when the various deeply magic tag
bits move somewhere else.
* eval.c: changed the locals used to store results of SCM_IFRAME,
scm_ilength and such to be of type scm_bits_t (and not int/long).
(iqq): depth, edepth: int -> scm_bits_t
(scm_eval_stack): int -> scm_bits_t
(SCM_CEVAL): various vars are not scm_bits_t instead of int.
(check_map_args, scm_map, scm_for_each): len: long -> scm_bits_t
i: int -> scm_bits_t
* environments.c: changed the many calls to scm_ulong2num to
scm_ubits2num.
(import_environment_fold): proc_as_ul: ulong -> scm_ubits_t
* dynwind.c (scm_dowinds): delta: long -> scm_bits_t
* debug.h: type renaming:
scm_debug_info -> scm_debug_info_t
scm_debug_frame -> scm_debug_frame_t
the old names are deprecated, all in-Guile uses changed.
(scm_debug_eframe_size): int -> scm_bits_t
* debug.c (scm_init_debug): use scm_c_define instead of the
deprecated scm_define.
* continuations.h: type renaming:
scm_contregs -> scm_contregs_t
the old name is deprecated, all in-Guile uses changed.
(scm_contregs_t.num_stack_items): size_t -> scm_bits_t
(scm_contregs_t.num_stack_items): ulong -> scm_ubits_t
* continuations.c (scm_make_continuation): change the type of
stack_size form long to scm_bits_t.
* ports.h: type renaming:
scm_port_rw_active -> scm_port_rw_active_t (and made a typedef)
scm_port -> scm_port_t
scm_ptob_descriptor -> scm_ptob_descriptor_t
the old names are deprecated, all in-Guile uses changed.
(scm_port_t.entry): int -> scm_bits_t.
(scm_port_t.line_number): int -> long.
(scm_port_t.putback_buf_size): int -> size_t.
* __scm.h (long_long, ulong_long): deprecated (they pollute the
global namespace and have little value besides that).
(SCM_BITS_LENGTH): new, is the bit size of scm_bits_t (i.e. of an
SCM handle).
(ifdef spaghetti): include sys/types.h and sys/stdtypes.h, if they
exist (for size_t & ptrdiff_t)
(scm_sizet): deprecated.
* Makefile.am (noinst_HEADERS): add num2integral.i.c
name for a Scheme object (now a void*), and SCM as 32 bit word for
storing tags and immediates (now a long int). Introduced
SCM_ASWORD and SCM_ASSCM for conversion. Fixed various dubious
code in the process: arbiter.c (use macros), unif.c (scm_array_p),
added append docs from R4RS.
* strings.c: Docstring typo fix, + eliminate unneeded IMP tests.
Thanks Dirk Hermann!
* chars.h: Provide SCM_CHARP, SCM_CHAR, SCM_MAKE_CHAR and
deprecate SCM_ICHRP, SCM_ICHR, SCM_MAKICHR. Thanks Dirk Hermann!
* *.h, *.c: Use SCM_CHARP, SCM_CHAR, SCM_MAKE_CHAR throughout.
Drop use of SCM_P for function prototypes... assume an ANSI C
compiler. Thanks Dirk Hermann!
scmsigs.c, strports.c, vports.c: Install the sources which
actually correspond to the changes described below. I got the
ChangeLog entries and the patch from two different places...
strports.c: take care of rw_active and rw_randow.
fports.c: scm_fport_drain_input: removed. do it all in ports.c.
strports.c (scm_mkstrport): check that pos is reasonable.
ioext.c (scm_ftell, scm_fseek): use lseek.
(SCM_CLEAR_BUFFERS): macro deleted.
ioext.c (redirect_port: use ptob fflush, read_flush.
ports.h (scm_ptobfuns): add ftruncate.
ports.c (scm_newptob): set ftruncate.
adjust ptob tables.
* ports.c (scm_ftruncate): new procedure.
fports.c (local_ftrunate), strports.c (str_ftruncate): new procs.
strports.c (st_seek, st_grow_port): new procs.
fports.h (scm_port): change size types from int to off_t.
ports.c (scm_init_ports): initialise the seek symbols here
instead of in ioext.c.
strports.c (scm_call_with_output_string): start with an empty
string, so seek and ftruncate can be used.
* ports.h (scm_ptobfuns): add a read_flush procedure which is the
equivalent to fflush for the read buffer.
* ports.c (scm_newptob): set read_flush.
ports.c (void_port_ptob): set read_flush.
fports.c (local_read_flush): new proc. add to ptob.
strport.c (st_read_flush): likewise.
vport.c (sf_read_flush): likewise.
fports.h (struct scm_fport): remove random member. there's nothing
left but fdes. leaving it as a struct to allow for future changes.
fports.c: replace usage of scm_fport::random with scm_port::rw_random.
ports.c: (scm_putc, scm_puts, scm_lfwrite): call the read_flush
ptob proc if the read buffer is filled.
* fports.h (SCM_FPORT_CLEAR_BUFFERS): rename to SCM_CLEAR_BUFFERS
and move to ioext.c.
* fports.h (SCM_MAYBE_DRAIN_INPUT): moved to ports.c.
use ptob for seek. take ptob instead of fport arg.
* fports.h (SCM_FDES_RANDOM_P): new macro. use it in
scm_fdes_to_port and scm_redirect_port.
* fports.h (SCM_CLEAR_BUFFERS): new macro.
* fports.h (SCM_FPORT_FDES): new macro.
* posix.c (scm_pipe): use fport buffer.
* unif.c: include fports.h instead of genio.h.
* fports.c (scm_fdes_wait_for_input, scm_fport_fill_buffer): new
procedures.
(local_fgetc): use them.
(local_ffwrite): use buffer.
(local_fgets): use buffer.
(scm_setbuf0): deleted.
(scm_setvbuf): set the buffer.
(scm_setfileno): deleted.
(scm_evict_ports): set fdes directly.
* (scm_freopen): deleted. doesn't seem useful in Guile.
(scm_stdio_to_port): deleted.
fports.h (struct scm_fport): add shortbuf member to avoid separate
code for unbuffered ports.
(SCM_FPORTP, SCM_OPFPORTP, SCM_OPINFPORTP, SCM_OPOUTFPORTP): moved
from ports.h.
* fports.c, fports.h (scm_fport_drain_input): new procedure.
* ports.c (scm_drain_input): call scm_fport_drain_input.
* scm_fdes_waiting_p: new procedure.
* fports.c (scm_fdes_to_port): allocate read and/or write buffers.
(scm_input_waiting_p): check the buffer.
(local_fgetc, local_fflush, local_fputc): likewise.
* fports.h (scm_fport): read/write_buf,_pos,_buf_end,,_buf_size:
new members.
* init.c (scm_init_standard_ports): pass fdes instead of FILE *.
* * ports.c (scm_drain_input): new procedure.
ports.h: prototype.
* fports.c (FPORT_READ_SAFE, FPORT_WRITE_SAFE, FPORT_ALL_OKAY,
pre_read, pre_write): removed.
(local_fputc, local_fputs, local_ffwrite): use write, not stdio.
(scm_standard_stream_to_port): change first arg from FILE * to
int fdes.
(local_fflush): flush fdes, not FILE *.
* fports.h (SCM_NOFTELL): removed.
* genio.c, ports.c: don't include filesys.h.
* genio.c (scm_getc): don't use scm_internal_select if FPORT.
do it in fports.c:local_fgetc.
* genio.c: don't use SCM_SYSCALL when calling ptob procedures.
do it where it's needed in the port smobs.
* filesys.c (scm_input_waiting_p): moved to fports.c, stdio
buffer support removed. take SCM arg, not FILE *.
* filesys.h: prototype moved too.
* fports.c (scm_fdes_to_port): new procedure.
(local_fgetc): use read not fgetc.
(local_fclose): use close, not fclose.
(local_fgets): use read, not fgets
* fports.h: prototype for scm_fdes_to_port.
* fports.h (scm_fport): new struct.
* fports.c (scm_open_file): use open, not fopen.
#include fcntl.h
* ports.h (struct scm_port_table): change stream from SCM to void *.
* ports.c (scm_add_to_port_table): check for memory allocation error.
(scm_prinport): remove MSDOS hair.
(scm_void_port): set stream to 0 instead of SCM_BOOL_F.
(scm_close_port): don't throw errors: do it in fports.c.
scm_evict_ports, scm_open_file, scm_stdio_to_port): Get rid of
SCM_P macro.
Centralize the creation of port objects based on stdio FILE * in
fports.c; don't just throw them together anywhere.
* fports.c (scm_stdio_to_port): Make NAME a SCM value, which is
what the rest of Guile wants. Don't set the revealed count;
that's only appropriate for stdin, stdout, stderr.
(scm_standard_stream_to_port): This function does set the revealed
count.
* init.c (scm_init_standard_ports): Use scm_standard_stream_to_port,
not scm_stdio_to_port.
* filesys.c (scm_open): Call scm_stdio_to_port; don't write it out.
* fports.c (scm_open_file): Same.
* posix.c (scm_pipe): Same.
* socket.c (scm_sock_fd_to_port): Same.
* ioext.c (scm_fdopen): Same.
(scm_freopen): Moved from here to...
* fports.c (scm_freopen): ... here. This is really something that
munges the internals of an fport, so it should go here.
* fports.h (scm_stdio_to_port): Adjust prototype.
(scm_standard_stream_to_port, scm_freopen): New protoypes.
* ioext.h (scm_freopen): Prototype removed.
* ioext.c (scm_dup_to_fdes): renamed from scm_primitive_dup2.
Scheme name is now dup->fdes.
(scm_dup_to_fdes): make the second argument optional and
fold in the functionality of scm_primitive_dup.
(scm_primitive_dup): deleted.
* fports.h (SCM_P): prototypes for scm_setvbuf, scm_setfileno.
* fports.c (scm_setbuf0): don't disable the setbuf if MSDOS or
ultrix are defined. Use setvbuf instead of setbuf.
(scm_setvbuf): new procedure.
(scm_init_fports): intern _IOFBF, _IOLBF, _IONBF.
(scm_setfileno): moved from ioext.c.
(scm_fgets): cast SCM_STREAM to (FILE *), remove unused lp variable.
(top of file): Delete 25 lines of probably obsolete CPP hair for MSDOS.
* boot-9.scm (move->fdes, dup->port): use dup->fdes, not primitive-dup.
(dup->fdes): deleted, now done in C.
SCM_THREAD_CRITICAL_SECTION_START/END unless USE_THREADS is defined.
* ports.h: prototypes too.
* ports.c (scm_mode_bits, scm_port_mode): moved from fports.c.
* fports.h: prototype too.
* fports.c (scm_evict_ports): moved from ioext.c.
* ports.c (scm_close_port): return a boolean instead of unspecified.
throw an error if an error other than EBADF occurs.
* filesys.h: scm_close prototype.
* filesys.c (scm_close): new procedure, can close file descriptors
and ports (scsh compatible).
* ports.c (scm_flush_all_ports): SCM_PROC incorrectly allowed an
optional argument.
wan't defined. Don't include fd.h.
* Previously fd.h was regenerated whenever configure was run,
forcing a couple of files to be recompiled.
* fd.h.in: deleted, SET_FILE_FD_FIELD moved to ioext.c.
* configure.in: AC_DEFINE FD_SETTER instead of HAVE_FD_SETTER.
Check for _fileno as well as _file.
Don't output fd.h.
* ioext.c: don't fd.h.
* acconfig.h: remove duplicate HAVE_FD_SETTER and change the
other to FD_SETTER.
* Change the stratigy for getting information about errno
(and now signal number) values, e.g., ENOSYS, SIGKILL. Instead of
generating lists of symbols during the build process, which will
not always work, include comprehensive lists in the distribution.
To help keep the lists up to date, the "check_signals" and
"check_errnos" make targets can be used.
* configure.in: don't check for a command to extract errno codes.
* Makefile.am: update file lists, remove errnos.list and errnos.c
targets, add cpp_err_symbols.c, cpp_sig_symbols.c, check_signals,
check_errnos targets.
(CLEANFILES): remove errnos.c and errnos.list, add
cpp_err_symbols_here cpp_err_symbols_diff cpp_err_symbols_new
cpp_sig_symbols_here cpp_sig_symbols_diff cpp_sig_symbols_new
* errnos.default: deleted.
* cpp_signal.c: new file.
* cpp_errno.c: renamed from errnos_get.c.
* cpp_err_symbols, cpp_sig_symbols: new files.
* cpp_cnvt.awk: renamed from errnos_cnvt_awk.
* error.c (scm_init_error): #include cpp_err_symbols instead of
errnos.c.
* posix.c (scm_init_posix): don't intern signal symbols. #include
cpp_sig_symbols.c.
* strop.c (scm_i_index): allow the lower bound to be equal to the
length of the string, so a null string doesn't always give an error.
* posix.h: new prototypes.
* posix.c (scm_status_exit_val, scm_status_term_sig,
scm_status_stop_sig): new functions, as in scsh. They break down
process status values as returned by waitpid.
