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Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" FileHandle \- supply object methods for filehandles .SH "SYNOPSIS" .IX Header "SYNOPSIS" .Vb 1 \& use FileHandle; \& \& $fh = FileHandle\->new; \& if ($fh\->open("< file")) { \& print <$fh>; \& $fh\->close; \& } \& \& $fh = FileHandle\->new("> FOO"); \& if (defined $fh) { \& print $fh "bar\en"; \& $fh\->close; \& } \& \& $fh = FileHandle\->new("file", "r"); \& if (defined $fh) { \& print <$fh>; \& undef $fh; # automatically closes the file \& } \& \& $fh = FileHandle\->new("file", O_WRONLY|O_APPEND); \& if (defined $fh) { \& print $fh "corge\en"; \& undef $fh; # automatically closes the file \& } \& \& $pos = $fh\->getpos; \& $fh\->setpos($pos); \& \& $fh\->setvbuf($buffer_var, _IOLBF, 1024); \& \& ($readfh, $writefh) = FileHandle::pipe; \& \& autoflush STDOUT 1; .Ve .SH "DESCRIPTION" .IX Header "DESCRIPTION" \&\s-1NOTE:\s0 This class is now a front-end to the IO::* classes. .PP \&\f(CW\*(C`FileHandle::new\*(C'\fR creates a \f(CW\*(C`FileHandle\*(C'\fR, which is a reference to a newly created symbol (see the \f(CW\*(C`Symbol\*(C'\fR package). If it receives any parameters, they are passed to \f(CW\*(C`FileHandle::open\*(C'\fR; if the open fails, the \f(CW\*(C`FileHandle\*(C'\fR object is destroyed. Otherwise, it is returned to the caller. .PP \&\f(CW\*(C`FileHandle::new_from_fd\*(C'\fR creates a \f(CW\*(C`FileHandle\*(C'\fR like \f(CW\*(C`new\*(C'\fR does. It requires two parameters, which are passed to \f(CW\*(C`FileHandle::fdopen\*(C'\fR; if the fdopen fails, the \f(CW\*(C`FileHandle\*(C'\fR object is destroyed. Otherwise, it is returned to the caller. .PP \&\f(CW\*(C`FileHandle::open\*(C'\fR accepts one parameter or two. With one parameter, it is just a front end for the built-in \f(CW\*(C`open\*(C'\fR function. With two parameters, the first parameter is a filename that may include whitespace or other special characters, and the second parameter is the open mode, optionally followed by a file permission value. .PP If \f(CW\*(C`FileHandle::open\*(C'\fR receives a Perl mode string (\*(L">\*(R", \*(L"+<\*(R", etc.) or a \s-1POSIX\s0 \fBfopen()\fR mode string (\*(L"w\*(R", \*(L"r+\*(R", etc.), it uses the basic Perl \f(CW\*(C`open\*(C'\fR operator. .PP If \f(CW\*(C`FileHandle::open\*(C'\fR is given a numeric mode, it passes that mode and the optional permissions value to the Perl \f(CW\*(C`sysopen\*(C'\fR operator. For convenience, \f(CW\*(C`FileHandle::import\*(C'\fR tries to import the O_XXX constants from the Fcntl module. If dynamic loading is not available, this may fail, but the rest of FileHandle will still work. .PP \&\f(CW\*(C`FileHandle::fdopen\*(C'\fR is like \f(CW\*(C`open\*(C'\fR except that its first parameter is not a filename but rather a file handle name, a FileHandle object, or a file descriptor number. .PP If the C functions \fBfgetpos()\fR and \fBfsetpos()\fR are available, then \&\f(CW\*(C`FileHandle::getpos\*(C'\fR returns an opaque value that represents the current position of the FileHandle, and \f(CW\*(C`FileHandle::setpos\*(C'\fR uses that value to return to a previously visited position. .PP If the C function \fBsetvbuf()\fR is available, then \f(CW\*(C`FileHandle::setvbuf\*(C'\fR sets the buffering policy for the FileHandle. The calling sequence for the Perl function is the same as its C counterpart, including the macros \f(CW\*(C`_IOFBF\*(C'\fR, \f(CW\*(C`_IOLBF\*(C'\fR, and \f(CW\*(C`_IONBF\*(C'\fR, except that the buffer parameter specifies a scalar variable to use as a buffer. \s-1WARNING: A\s0 variable used as a buffer by \f(CW\*(C`FileHandle::setvbuf\*(C'\fR must not be modified in any way until the FileHandle is closed or until \&\f(CW\*(C`FileHandle::setvbuf\*(C'\fR is called again, or memory corruption may result! .PP See perlfunc for complete descriptions of each of the following supported \f(CW\*(C`FileHandle\*(C'\fR methods, which are just front ends for the corresponding built-in functions: .PP .Vb 8 \& close \& fileno \& getc \& gets \& eof \& clearerr \& seek \& tell .Ve .PP See perlvar for complete descriptions of each of the following supported \f(CW\*(C`FileHandle\*(C'\fR methods: .PP .Vb 12 \& autoflush \& output_field_separator \& output_record_separator \& input_record_separator \& input_line_number \& format_page_number \& format_lines_per_page \& format_lines_left \& format_name \& format_top_name \& format_line_break_characters \& format_formfeed .Ve .PP Furthermore, for doing normal I/O you might need these: .ie n .IP "$fh\->print" 4 .el .IP "\f(CW$fh\fR\->print" 4 .IX Item "$fh->print" See \*(L"print\*(R" in perlfunc. .ie n .IP "$fh\->printf" 4 .el .IP "\f(CW$fh\fR\->printf" 4 .IX Item "$fh->printf" See \*(L"printf\*(R" in perlfunc. .ie n .IP "$fh\->getline" 4 .el .IP "\f(CW$fh\fR\->getline" 4 .IX Item "$fh->getline" This works like <$fh> described in \*(L"I/O Operators\*(R" in perlop except that it's more readable and can be safely called in a list context but still returns just one line. .ie n .IP "$fh\->getlines" 4 .el .IP "\f(CW$fh\fR\->getlines" 4 .IX Item "$fh->getlines" This works like <$fh> when called in a list context to read all the remaining lines in a file, except that it's more readable. It will also \fBcroak()\fR if accidentally called in a scalar context. .PP There are many other functions available since FileHandle is descended from IO::File, IO::Seekable, and IO::Handle. Please see those respective pages for documentation on more functions. .SH "SEE ALSO" .IX Header "SEE ALSO" The \fB\s-1IO\s0\fR extension, perlfunc, \&\*(L"I/O Operators\*(R" in perlop.