perlapio
Current Perl documentation can be found at
perldoc.perl.org.
Here is our local, out-dated (pre-5.6) version:
perlapio - perl's
IO abstraction interface.
PerlIO *PerlIO_stdin(void);
PerlIO *PerlIO_stdout(void);
PerlIO *PerlIO_stderr(void);
PerlIO *PerlIO_open(const char *,const char *);
int PerlIO_close(PerlIO *);
int PerlIO_stdoutf(const char *,...)
int PerlIO_puts(PerlIO *,const char *);
int PerlIO_putc(PerlIO *,int);
int PerlIO_write(PerlIO *,const void *,size_t);
int PerlIO_printf(PerlIO *, const char *,...);
int PerlIO_vprintf(PerlIO *, const char *, va_list);
int PerlIO_flush(PerlIO *);
int PerlIO_eof(PerlIO *);
int PerlIO_error(PerlIO *);
void PerlIO_clearerr(PerlIO *);
int PerlIO_getc(PerlIO *);
int PerlIO_ungetc(PerlIO *,int);
int PerlIO_read(PerlIO *,void *,size_t);
int PerlIO_fileno(PerlIO *);
PerlIO *PerlIO_fdopen(int, const char *);
PerlIO *PerlIO_importFILE(FILE *, int flags);
FILE *PerlIO_exportFILE(PerlIO *, int flags);
FILE *PerlIO_findFILE(PerlIO *);
void PerlIO_releaseFILE(PerlIO *,FILE *);
void PerlIO_setlinebuf(PerlIO *);
long PerlIO_tell(PerlIO *);
int PerlIO_seek(PerlIO *,off_t,int);
int PerlIO_getpos(PerlIO *,Fpos_t *)
int PerlIO_setpos(PerlIO *,Fpos_t *)
void PerlIO_rewind(PerlIO *);
int PerlIO_has_base(PerlIO *);
int PerlIO_has_cntptr(PerlIO *);
int PerlIO_fast_gets(PerlIO *);
int PerlIO_canset_cnt(PerlIO *);
char *PerlIO_get_ptr(PerlIO *);
int PerlIO_get_cnt(PerlIO *);
void PerlIO_set_cnt(PerlIO *,int);
void PerlIO_set_ptrcnt(PerlIO *,char *,int);
char *PerlIO_get_base(PerlIO *);
int PerlIO_get_bufsiz(PerlIO *);
Perl's source code should use the above functions instead of those defined in
ANSI C's
stdio.h. The perl headers will #define them to the
I/O mechanism selected at Configure time.
The functions are modeled on those in stdio.h, but parameter order has been ``tidied up a little''.
- PerlIO *
-
This takes the place of
FILE *. Like
FILE * it should be treated as opaque (it is probably safe to assume it is a pointer to something).
- PerlIO_stdin(), PerlIO_stdout(), PerlIO_stderr()
-
Use these rather than
stdin , stdout , stderr . They are written to look like ``function calls'' rather than variables
because this makes it easier to make them function calls if platform cannot export data to loaded modules, or if
(say) different ``threads'' might have different values.
- PerlIO_open(path, mode), PerlIO_fdopen(fd,mode)
-
These correspond to
fopen()/fdopen()
arguments are the same.
- PerlIO_printf(f,fmt,...), PerlIO_vprintf(f,fmt,a)
-
These are
fprintf()/vfprintf()
equivalents.
- PerlIO_stdoutf(fmt,...)
-
This is
printf() equivalent. printf
is #defined to this function, so it is (currently) legal to use printf(fmt,...) in perl sources.
- PerlIO_read(f,buf,count), PerlIO_write(f,buf,count)
-
These correspond to
fread() and
fwrite(). Note that arguments are different, there is only one ``count'' and order has ``file'' first.
- PerlIO_close(f)
-
- PerlIO_puts(f,s), PerlIO_putc(f,c)
-
These correspond to
fputs() and
fputc(). Note that arguments have been revised to have ``file'' first.
- PerlIO_ungetc(f,c)
-
This corresponds to
ungetc(). Note that arguments
have been revised to have ``file'' first.
- PerlIO_getc(f)
-
This corresponds to
getc().
- PerlIO_eof(f)
-
This corresponds to
feof().
- PerlIO_error(f)
-
This corresponds to
ferror().
- PerlIO_fileno(f)
-
This corresponds to
fileno(), note that on some
platforms, the meaning of ``fileno'' may not match Unix.
- PerlIO_clearerr(f)
-
This corresponds to
clearerr(), i.e., clears
'eof' and 'error' flags for the ``stream''.
- PerlIO_flush(f)
-
This corresponds to
fflush().
- PerlIO_tell(f)
-
This corresponds to
ftell().
- PerlIO_seek(f,o,w)
-
This corresponds to
fseek().
- PerlIO_getpos(f,p), PerlIO_setpos(f,p)
-
These correspond to
fgetpos() and
fsetpos(). If platform does not have the stdio calls then they are implemented in terms of
PerlIO_tell() and
PerlIO_seek().
- PerlIO_rewind(f)
-
This corresponds to
rewind(). Note may be redefined in terms of
PerlIO_seek() at some point.
- PerlIO_tmpfile()
-
This corresponds to
tmpfile(), i.e., returns an
anonymous PerlIO which will automatically be deleted when closed.
There is outline support for co-existence of PerlIO with stdio. Obviously if PerlIO is implemented in terms of stdio there is no problem. However if perlio is implemented on top of (say) sfio then mechanisms must exist to create a
FILE * which can be passed to library code which is going to use stdio calls.
- PerlIO_importFILE(f,flags)
-
Used to get a PerlIO * from a
FILE *. May need additional arguments, interface under
review.
- PerlIO_exportFILE(f,flags)
-
Given an PerlIO * return a 'native'
FILE * suitable for passing to code expecting to be compiled and linked with
ANSI
C
stdio.h.
The fact that such a
FILE * has been 'exported' is recorded, and may affect
future PerlIO operations on the original PerlIO *.
- PerlIO_findFILE(f)
-
Returns previously 'exported'
FILE * (if any). Place holder until interface is fully
defined.
- PerlIO_releaseFILE(p,f)
-
Calling PerlIO_releaseFILE informs PerlIO that all use of
FILE * is complete. It is removed from list of 'exported'
FILE *s, and associated PerlIO * should revert to original behaviour.
- PerlIO_setlinebuf(f)
-
This corresponds to
setlinebuf(). Use is
deprecated pending further discussion. (Perl core uses it only when ``dumping''; it has nothing to do with $| auto-flush.)
In addition to user
API above there is an ``implementation'' interface
which allows perl to get at internals of PerlIO. The following calls
correspond to the various FILE_xxx macros determined by Configure. This
section is really of interest to only those concerned with detailed
perl-core behaviour or implementing a PerlIO mapping.
- PerlIO_has_cntptr(f)
-
Implementation can return pointer to current position in the ``buffer'' and
a count of bytes available in the buffer.
- PerlIO_get_ptr(f)
-
Return pointer to next readable byte in buffer.
- PerlIO_get_cnt(f)
-
Return count of readable bytes in the buffer.
- PerlIO_canset_cnt(f)
-
Implementation can adjust its idea of number of bytes in the buffer.
- PerlIO_fast_gets(f)
-
Implementation has all the interfaces required to allow perl's fast code to handle
<FILE> mechanism.
PerlIO_fast_gets(f) = PerlIO_has_cntptr(f) && \
PerlIO_canset_cnt(f) && \
`Can set pointer into buffer'
- PerlIO_set_ptrcnt(f,p,c)
-
Set pointer into buffer, and a count of bytes still in the buffer. Should
be used only to set pointer to within range implied by previous calls to
PerlIO_get_ptr and PerlIO_get_cnt .
- PerlIO_set_cnt(f,c)
-
Obscure - set count of bytes in the buffer. Deprecated. Currently used in
only doio.c to force count < -1 to -1. Perhaps should be
PerlIO_set_empty or similar. This call may actually do nothing if ``count''
is deduced from pointer and a ``limit''.
- PerlIO_has_base(f)
-
Implementation has a buffer, and can return pointer to whole buffer and its
size. Used by perl for -T / -B tests. Other uses would be very obscure...
- PerlIO_get_base(f)
-
Return start of buffer.
- PerlIO_get_bufsiz(f)
-
Return total size of buffer.
Return to the Library
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