Yes, each bg proc needs its own output file or pipe, unless you can ensure they write() blocks of whole lines. I had to clean up some shared logs in C/C++, using setvbuf() to make the log's FILE* buffer big, and fflush() to ship each buffered message in a single write(). In shell, you might have problems ensuring atomic line write(). If you want sorted outputsort can be a buffer:
i just finished a project for a c++ class that i wrote at home on my computer, compiled with gcc. when i brought the code into school it would not compile, it would complain that cannot call main() function. at school we use ancient borland c++ from 1995. anyway my program has 20 different... (3 Replies)
I wrote a script in ksh93 (the OS is AIX 5.2, ML7), which failed to run. After some testing i found out why, but the answer is a bit dissatisfying. Look for yourself:
#!/bin/ksh93
# --------- Step Names
typeset achStepName="foo"
typeset achStepName="bar"
typeset achStepName="fubar"... (3 Replies)
Hi,
I have a main loop which calls a sub loop, which finally returns to the main loop itself. The main loop runs when a flag is set. Now, I have a signal handler for SIGINT, which resets the flag and thus stops the main loop. Suppose I send SIGINT while the program is in subloop, I get an error... (1 Reply)
Hi! I've a C program as shown below..
The line numbers and the statements of the program are separated by a space..
1 #include<stdio.h>
2 char a,b,c;
3 float x,y,z;
4 int main()
5 {
6 int d,e,f;
7 // further declarations
8 // further declarations
9 /* body*/
10 }
11 void fun1()
12... (1 Reply)
Hi friends,
when I am passing arguments to main, I want another function to be able to have access to that function, the problem is that I am creating athread, which has a function like void *xyz(void *), how can pass the refernce of argv to this function, if you see my program, you will better... (2 Replies)
H friends,
As we know, a function returns a value and that value is saved somwhere. like
int Sum( int x, int y )
{
return x + y;
}
Total = Sum( 10, 20 );
The value 30 is saved in variable Total.
Now the question is, what int value does the function main return, and where is it... (5 Replies)
A sample.c file is written with only one single statement.
main;
Segmentation fault occurred when executed that file.
Any statement other than main; is written, for example unix; then it won't compile.
why is this behaviour ! (2 Replies)
Hi Experts,
I have several shell scripts that have been developed on a Linux box for korn ksh93.
If we want to run this software on an AIX 6.1 box that runs ksh88 by default can we just change the she-bang line to reference /bin/ksh93 which ships with AIX as its "enhanced shell" to ensure... (6 Replies)
Hi. I have some code, that for some reason, I could not post it here in this post. Here's the address for it:
#if 0 shc Version 4.0.1, Generic Shell Script Compiler GNU GPL Version 3 Md - Pastebin.com
First off, I used "shc" to convert the code from shell script to C.
And The... (6 Replies)
Discussion started by: ignatius
6 Replies
LEARN ABOUT DEBIAN
setbuffer
SETBUF(3) Linux Programmer's Manual SETBUF(3)NAME
setbuf, setbuffer, setlinebuf, setvbuf - stream buffering operations
SYNOPSIS
#include <stdio.h>
void setbuf(FILE *stream, char *buf);
void setbuffer(FILE *stream, char *buf, size_t size);
void setlinebuf(FILE *stream);
int setvbuf(FILE *stream, char *buf, int mode, size_t size);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
setbuffer(), setlinebuf(): _BSD_SOURCE
DESCRIPTION
The three types of buffering available are unbuffered, block buffered, and line buffered. When an output stream is unbuffered, information
appears on the destination file or terminal as soon as written; when it is block buffered many characters are saved up and written as a
block; when it is line buffered characters are saved up until a newline is output or input is read from any stream attached to a terminal
device (typically stdin). The function fflush(3) may be used to force the block out early. (See fclose(3).) Normally all files are block
buffered. When the first I/O operation occurs on a file, malloc(3) is called, and a buffer is obtained. If a stream refers to a terminal
(as stdout normally does) it is line buffered. The standard error stream stderr is always unbuffered by default.
The setvbuf() function may be used on any open stream to change its buffer. The mode argument must be one of the following three macros:
_IONBF unbuffered
_IOLBF line buffered
_IOFBF fully buffered
Except for unbuffered files, the buf argument should point to a buffer at least size bytes long; this buffer will be used instead of the
current buffer. If the argument buf is NULL, only the mode is affected; a new buffer will be allocated on the next read or write opera-
tion. The setvbuf() function may only be used after opening a stream and before any other operations have been performed on it.
The other three calls are, in effect, simply aliases for calls to setvbuf(). The setbuf() function is exactly equivalent to the call
setvbuf(stream, buf, buf ? _IOFBF : _IONBF, BUFSIZ);
The setbuffer() function is the same, except that the size of the buffer is up to the caller, rather than being determined by the default
BUFSIZ. The setlinebuf() function is exactly equivalent to the call:
setvbuf(stream, NULL, _IOLBF, 0);
RETURN VALUE
The function setvbuf() returns 0 on success. It returns nonzero on failure (mode is invalid or the request cannot be honored). It may set
errno on failure.
The other functions do not return a value.
CONFORMING TO
The setbuf() and setvbuf() functions conform to C89 and C99.
BUGS
The setbuffer() and setlinebuf() functions are not portable to versions of BSD before 4.2BSD, and are available under Linux since libc
4.5.21. On 4.2BSD and 4.3BSD systems, setbuf() always uses a suboptimal buffer size and should be avoided.
You must make sure that the space that buf points to still exists by the time stream is closed, which also happens at program termination.
For example, the following is invalid:
#include <stdio.h>
int
main(void)
{
char buf[BUFSIZ];
setbuf(stdin, buf);
printf("Hello, world!
");
return 0;
}
SEE ALSO fclose(3), fflush(3), fopen(3), fread(3), malloc(3), printf(3), puts(3)COLOPHON
This page is part of release 3.44 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
Linux 2012-08-03 SETBUF(3)