Flashnux

GNU/Linux man pages

Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :

ISBN : 978-2-7460-9712-4
EAN : 9782746097124
(Editions ENI)

Unix

Unix v7

brk(2)


BRK

BRK

NAME
SYNOPSIS
DESCRIPTION
SEE ALSO
DIAGNOSTICS
BUGS
ASSEMBLER

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. Ordinarily, 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 registers 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)