![]() ![]() This isn't as hard on your system as unbuffering, but does get the output where you want it when you want it. What it does instead support is "command buffering", in which a physical write is performed after every output command. Perl does not support truly unbuffered output (except insofar as you can syswrite(OUT, $char, 1)). modems, terminals) are normally line-buffered, and stdio sends the entire line when it gets the newline. Pipes and sockets are often buffered with a buffer size between 1/2 and 2k. Disk files are block buffered, often with a buffer size of more than 2k. In most stdio implementations, the type of output buffering and the size of the buffer varies according to the type of device. syswrite() circumvents stdio and buffering. Any time you use print() or write() in Perl, you go though this buffering. This is done for efficiency reasons, so that there isn't a system call for each byte. The C standard I/O library (stdio) normally buffers characters sent to devices. # How do I flush/unbuffer an output filehandle? Why must I do this? This section deals with I/O and the "f" issues: filehandles, flushing, formats, and footers. Perlfaq5 - Files and Formats ($Revision: 1.24 $, $Date: 5 15:07:20 $) #DESCRIPTION How do I select a random line from a file?.Why does Perl let me delete read-only files? Why does -i clobber protected files? Isn't this a bug in Perl?.Why doesn't glob("*.*") get all the files?.Why can't I use "C:\temp\foo" in DOS paths? What doesn't `C:\temp\foo.exe` work?.How do I close a file descriptor by number?.How can I tell if there's a character waiting on a filehandle?.How can I read a single character from a file? From the keyboard?.How can I read in a file by paragraphs?.How do I print to more than one file at once?.How do I set a file's timestamp in perl?.How do I get a file's timestamp in perl?. NAME MANGLER INCREMENT REGULAR EXPRESSION UPDATEHow do I randomly update a binary file?.I just want to increment the number in the file. What can't I just open(FH, ">file.lock")?.How can I open a file with a leading ">" or trailing blanks?.Why do I sometimes get an "Argument list too long" when I use ?.How come when I open a file read-write it wipes it out?.How can I translate tildes (~) in a filename?.How can I output my numbers with commas added?.How can I set up a footer format to be used with write()?.How can I make a filehandle local to a subroutine? How do I pass filehandles between subroutines? How do I make an array of filehandles?.How can I manipulate fixed-record-length files?.How do I count the number of lines in a file?.How do I change one line in a file/delete a line in a file/insert a line in the middle of a file/append to the beginning of a file?.How do I flush/unbuffer an output filehandle? Why must I do this?.You are viewing the version of this documentation from Perl 5.005. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |