man.postnix Miscellaneous man pages of Plan 9 related material

     SEGBRK(2)                                               SEGBRK(2)

     NAME
          segbrk - change memory allocation

     SYNOPSIS
          #include <u.h>
          #include <libc.h>

          void* segbrk(void *saddr, void *addr)

     DESCRIPTION
          Segbrk sets the system's idea of the lowest unused location
          of a segment to addr rounded up to the next multiple of a
          page size, typically 4096 bytes.  The segment is identified
          by saddr which may be any valid address within the segment.

          A call to segbrk with a zero addr argument returns the
          address of the top of bss.

          The system will prevent segments from overlapping and will
          not allow the length of the text, data, or stack segment to
          be altered.

     SOURCE
          /sys/src/libc/9syscall

     SEE ALSO
          brk(2), segattach(2), segflush(2)
          /proc/*/segment

     DIAGNOSTICS
          Sets errstr. Segbrk returns (void*)-1 on error.

     BUGS
          Segbrk is not fully defined or implemented.  In particular,
          it cannot always return the top of bss when called with a
          zero addr argument.  The segbrk system call may go away or
          be re-implemented to give more general segment control, sub-
          suming the functions of brk(2), segflush(2) and segfree in
          segattach(2).

     Page 1                       Plan 9            (printed 12/22/24)