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Diffstat (limited to 'mcon/U/sbrksmart.U')
| -rw-r--r-- | mcon/U/sbrksmart.U | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/mcon/U/sbrksmart.U b/mcon/U/sbrksmart.U new file mode 100644 index 0000000..54755aa --- /dev/null +++ b/mcon/U/sbrksmart.U @@ -0,0 +1,84 @@ +?RCS: $Id: sbrksmart.U,v 3.0.1.2 1995/01/11 15:35:41 ram Exp $ +?RCS: +?RCS: Copyright (c) 1991-1993, Raphael Manfredi +?RCS: +?RCS: You may redistribute only under the terms of the Artistic Licence, +?RCS: as specified in the README file that comes with the distribution. +?RCS: You may reuse parts of this distribution only within the terms of +?RCS: that same Artistic Licence; a copy of which may be found at the root +?RCS: of the source tree for dist 3.0. +?RCS: +?RCS: $Log: sbrksmart.U,v $ +?RCS: Revision 3.0.1.2 1995/01/11 15:35:41 ram +?RCS: patch45: now sets sbrksmart to undef explicitely when lacking sbrk() +?RCS: patch45: forgot a cast when using return value from sbrk() +?RCS: +?RCS: Revision 3.0.1.1 1994/01/24 14:16:45 ram +?RCS: patch16: created +?RCS: +?MAKE:sbrksmart: cat d_sbrk +cc +ccflags +libs rm +?MAKE: -pick add $@ %< +?S:sbrksmart: +?S: This variable conditionally defines HAS_SMART_SBRK if the sbrk() +?S: routine honors a negative argument to lower the break value. +?S:. +?C:HAS_SMART_SBRK: +?C: This symbol is defined when the sbrk() system call may be used with +?C: a negative argument to lower the break value, therefore releasing +?C: core to the system. If not, you'd probably be better off using the +?C: mmap() system call. +?C:. +?H:#$sbrksmart HAS_SMART_SBRK /**/ +?H:. +?T:dumb +: see if sbrk can release core to the kernel +echo " " +case "$d_sbrk" in +"$define") + echo "Let's see if your sbrk() is smart enough to release core..." >&4 + $cat > sbrk.c <<'EOC' +#define INC 256 /* Small enough to be less than a page size */ + +main() +{ + char *obrk = (char *) sbrk(0); + char *nbrk; + + nbrk = (char *) sbrk(INC); + if (nbrk == (char *) -1) + exit(1); /* Not enough memory */ + if (nbrk != obrk) + exit(2); /* Unreliable sbrk() */ + nbrk = (char *) sbrk(-INC); + if (nbrk == (char *) -1) + exit(3); /* May have understood negative arg as huge positive */ + if (obrk != (char *) sbrk(0)) + exit(4); /* Not smart, definitely */ + + exit(0); /* Ok */ +} +EOC + sbrksmart="$undef" + dumb='-- assuming dumb sbrk().' + if $cc $ccflags -o sbrk sbrk.c $libs >/dev/null 2>&1; then + ./sbrk >/dev/null 2>&1 + case $? in + 0) sbrksmart="$define" + echo "Yes, it can be used with negative values." ;; + 1) echo "Sorry, not enough memory $dumb" ;; + 2) echo "No it's not, and besides it seems to be buggy..." ;; + 3) echo "No, it fails with negative values." ;; + 4) echo "Nope, your sbrk() is too dumb." ;; + *) echo "Err... Unexpected result $dumb" ;; + esac + else + echo "(Could not compile test program $dumb)" + fi + ;; +*) + echo "Since you don't have sbrk(), let's forget about the smart test!" + sbrksmart="$undef" + ;; +esac +$rm -f sbrk sbrk.* core + |