ref: c2a5d7e3f28e86aeef1e4e37e2b88e46af90b62c
dir: /sys/man/2/brk/
.TH BRK 2 .SH NAME brk, sbrk \- change memory allocation .SH SYNOPSIS .B #include <u.h> .br .B #include <libc.h> .PP .ta \w'\fLvoid* 'u .B int brk(void *addr) .PP .B void* sbrk(usize incr) .SH DESCRIPTION .I Brk sets the system's idea of the lowest bss location not used by the program (called the break) to .I addr rounded up to the next multiple of 8 bytes. Locations not less than .I addr and below the stack pointer may cause a memory violation if accessed. .PP In the alternate function .IR sbrk , .I 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 .IR brk . .PP When a program begins execution via .I 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 .IR brk . A call to .I sbrk with a zero argument returns the current break in the dynamic segment. .SH SOURCE .B /sys/src/libc/9sys/sbrk.c .SH SEE ALSO .IR intro (2), .IR malloc (2), .IR segattach (2), .IR segbrk (2) .SH DIAGNOSTICS These functions set .IR errstr . .PP The error return from .I sbrk is .BR (void*)-1 .