diff options
Diffstat (limited to 'mcon/U/Csym.U')
| -rw-r--r-- | mcon/U/Csym.U | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/mcon/U/Csym.U b/mcon/U/Csym.U new file mode 100644 index 0000000..45ff465 --- /dev/null +++ b/mcon/U/Csym.U @@ -0,0 +1,111 @@ +?RCS: $Id$ +?RCS: +?RCS: Copyright (c) 1991-1997, 2004-2006, Raphael Manfredi +?RCS: +?RCS: You may redistribute only under the terms of the Artistic License, +?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 License; a copy of which may be found at the root +?RCS: of the source tree for dist 4.0. +?RCS: +?RCS: $Log: Csym.U,v $ +?RCS: Revision 3.0.1.4 1995/07/25 13:36:29 ram +?RCS: patch56: re-arranged compile line to include ldflags before objects +?RCS: patch56: added quotes for OS/2 support +?RCS: +?RCS: Revision 3.0.1.3 1995/05/12 12:00:33 ram +?RCS: patch54: fixed C test program to bypass gcc builtin type checks (ADO) +?RCS: +?RCS: Revision 3.0.1.2 1994/10/31 09:34:13 ram +?RCS: patch44: added Options to the MAKE line since it's no longer in Init.U +?RCS: +?RCS: Revision 3.0.1.1 1993/08/25 14:00:05 ram +?RCS: patch6: added ldflags as a conditional dependency and to compile line +?RCS: patch6: a final double quote was missing in csym variable after eval +?RCS: +?RCS: Revision 3.0 1993/08/18 12:04:50 ram +?RCS: Baseline for dist 3.0 netwide release. +?RCS: +?MAKE:Csym: Options contains cat libc libs runnm +cc +ccflags +ldflags rm +?MAKE: -pick add $@ %< +?LINT:define csym +?LINT:use libc +?S:csym: +?S: This shell variable is used internally by Configure to check +?S: wether a given C symbol is defined or not. A typical use is: +?S: set symbol result [-fva] [previous] +?S: eval $csym +?S: That will set result to 'true' if the function [-f], variable [-v] +?S: or array [-a] is defined, 'false' otherwise. If a previous value is +?S: given and the -r flag was provided on the command line, that value +?S: is reused without questioning. +?S:. +?V:csym +?T:tval tx tlook tf tdc tc file +: is a C symbol defined? +csym='tlook=$1; +case "$3" in +-v) tf=libc.tmp; tc=""; tdc="";; +-a) tf=libc.tmp; tc="[0]"; tdc="[]";; +*) tlook="^$1\$"; tf=libc.list; tc=""; tdc="()";; +esac; +file=csym.log; +tx=yes; +case "$reuseval-$4" in +true-) ;; +true-*) tx=no; eval "tval=\$$4"; case "$tval" in "") tx=yes;; esac;; +esac; +case "$tx" in +yes) + case "$runnm" in + true) + if $contains $tlook $tf >/dev/null 2>&1; + then tval=true; + else tval=false; + fi;; + *) +?X: +?X: We use 'char' instead of 'int' to try to circumvent overzealous +?X: optimizing compilers using built-in prototypes for commonly used +?X: routines to complain when seeing a different external declaration. For +?X: instance, gcc 2.6.3 fails if we use 'int' and we attempt a test against +?X: memcpy() on machines where sizeof(int) == sizeof(char *) (the usual return +?X: type), the compiler assuming it's a built-in declaration given that the +?X: returned size matches. At least with 'char' we are safe! -- RAM, for ADO +?X: +?X: Let's thank GNU cc for making our lives so easy! :-) +?X: (An alternative for the future would be to use our knowledge about gcc +?X: to force a -fno-builtin option in the compile test, in case the 'char' +?X: trick is obsoleted by future gcc releases). -- RAM +?X: +?X: Lastly, gcc 3.4 optimizes &missing == 0 away, so we use + 2 instead now. +?X: The GNU folks like to do weird things, don't they? -- RAM, 2004-06-05 +?X +?X: The above was invalid because main returns an int not a pointer. +?X: Using != or == does not work because GCC complains the pointer will +?X: never be NULL if the function exists. It is a warning meant to prevent +?X: using an address of a function by accident instead of calling it. +?X: However, &missing > 0 is indeed silently optimized away. +?X +?X: FIXME: There must be a test whether non-existing functions are found! +?X: +?X:. -- cbiere, 2011-01-18 +?X: + echo "--- $1$tdc ---" >> "$file"; + echo "extern char $1$tdc; int main(void) { return (unsigned long) &$1$tc > 2; }" > t.c; + $cat t.c >> "$file"; + if $cc $ccflags $ldflags -o t t.c $libs >>"$file" 2>&1; + then tval=true; + else tval=false; + fi; + $rm -f t t.c;; + esac;; +*) + case "$tval" in + $define) tval=true;; + *) tval=false;; + esac;; +esac; +echo "==> HAS $1$tdc is $tval ($4)" >>"$file"; +eval "$2=$tval"' + |