Linux and UNIX Man Pages

Linux & Unix Commands - Search Man Pages

brk(2) [v7 man page]

BRK(2)								System Calls Manual							    BRK(2)

NAME
brk, sbrk, break - change core allocation SYNOPSIS
char *brk(addr) char *sbrk(incr) DESCRIPTION
Brk sets the system's idea of the lowest location not used by the program (called the break) to addr (rounded up to the next multiple of 64 bytes on the PDP11, 256 bytes on the Interdata 8/32, 512 bytes on the VAX-11/780). Locations not less than addr and below the stack pointer are not in the address space and will thus cause a memory violation if accessed. In the alternate function sbrk, incr more bytes are added to the program's data space and a pointer to the start of the new area is returned. When a program begins execution via exec the break is set at the highest location defined by the program and data storage areas. Ordinar- ily, therefore, only programs with growing data areas need to use break. SEE ALSO
exec(2), malloc(3), end(3) DIAGNOSTICS
Zero is returned if the break could be set; -1 if the program requests more memory than the system limit or if too many segmentation regis- ters would be required to implement the break. BUGS
Setting the break in the range 0177701 to 0177777 (on the PDP11) is the same as setting it to zero. ASSEMBLER
(break = 17.) sys break; addr Break performs the function of brk. The name of the routine differs from that in C for historical reasons. BRK(2)

Check Out this Related Man Page

BRK(2)								System Calls Manual							    BRK(2)

NAME
brk, sbrk - change memory allocation SYNOPSIS
#include <u.h> #include <libc.h> int brk(void *addr) void* sbrk(ulong incr) DESCRIPTION
Brk sets the system's idea of the lowest bss location not used by the program (called the break) to addr rounded up to the next multiple of 8 bytes. Locations not less than addr and below the stack pointer may cause a memory violation if accessed. In the alternate function sbrk, incr more bytes are added to the program's data space and a pointer to the start of the new area is returned. Rounding occurs as with brk. When a program begins execution via exec the break is set at the highest location defined by the program and data storage areas. Ordinar- ily, therefore, only programs with growing data areas need to use brk. A call to sbrk with a zero argument returns the lowest address in the dynamic segment. SOURCE
/sys/src/libc/9sys/sbrk.c SEE ALSO
intro(2), malloc(2), segattach(2), segbrk(2) DIAGNOSTICS
These functions set errstr. The error return from sbrk is (void*)-1. BRK(2)
Man Page

6 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

attempting to break within function

Attempting to break from a case/esac paragraph while inside of a function. When executing the code below, entering the letter 'a', will prove that the directory exists, but the break command works for the if/fi, but not for the case/esac. So, in my example below, if an A is entered, the function... (8 Replies)
Discussion started by: tumblez
8 Replies

2. Solaris

How send break in T5220 Box?

Hi, I used "send brk" from terminal in T5220 Box, but no response. Anyone know what's reason? Thanks! (7 Replies)
Discussion started by: xlen
7 Replies

3. Solaris

send break

Does anyone know how to send break on a Blade 100? I'm using a serial cable on my laptop and I can see the system boot up just fine, but I want to send break so i can have it boot from cdrom instead of disk. (3 Replies)
Discussion started by: em23
3 Replies

4. Programming

segmentation fault

Hi, I am having this segmentation fault not in the following program, bt. in my lab program . My lab program is horrible long so cannot post it here bt. I am using the following logic in my program which is giving the segmentation fault. Bt. if I run this sample program as it is it dosen't give... (3 Replies)
Discussion started by: mind@work
3 Replies

5. UNIX for Dummies Questions & Answers

How can I set DBX to break on an Access Violation?

I'm trying to debug a service crash, and would like to break on an access violation - is this possible? (0 Replies)
Discussion started by: ctote
0 Replies

6. UNIX for Dummies Questions & Answers

Find a string across line break (because of "segmentation fault core dumped")

Hi, thanks to a precedent post, and thanks to the reply of derekludwig of the forum, I have convert my first awk command as : test.txt is : AAAAAGHIJKLAjKMEFJKLjklABCDJkLEFGHIJKL awk -f findstring.awk test.txt > textreturn.txtfindstring.awk is : BEGIN{ SLENGTH = 3 } { ... (3 Replies)
Discussion started by: thewizarde6
3 Replies