| 1 | ?RCS: $Id: Csym.U,v 3.0.1.4 1995/07/25 13:36:29 ram Exp $ |
| 2 | ?RCS: |
| 3 | ?RCS: Copyright (c) 1991-1993, Raphael Manfredi |
| 4 | ?RCS: |
| 5 | ?RCS: You may redistribute only under the terms of the Artistic License, |
| 6 | ?RCS: as specified in the README file that comes with the distribution. |
| 7 | ?RCS: You may reuse parts of this distribution only within the terms of |
| 8 | ?RCS: that same Artistic License; a copy of which may be found at the root |
| 9 | ?RCS: of the source tree for dist 3.0. |
| 10 | ?RCS: |
| 11 | ?RCS: $Log: Csym.U,v $ |
| 12 | ?RCS: Revision 3.0.1.4 1995/07/25 13:36:29 ram |
| 13 | ?RCS: patch56: re-arranged compile line to include ldflags before objects |
| 14 | ?RCS: patch56: added quotes for OS/2 support |
| 15 | ?RCS: |
| 16 | ?RCS: Revision 3.0.1.3 1995/05/12 12:00:33 ram |
| 17 | ?RCS: patch54: fixed C test program to bypass gcc builtin type checks (ADO) |
| 18 | ?RCS: |
| 19 | ?RCS: Revision 3.0.1.2 1994/10/31 09:34:13 ram |
| 20 | ?RCS: patch44: added Options to the MAKE line since it's no longer in Init.U |
| 21 | ?RCS: |
| 22 | ?RCS: Revision 3.0.1.1 1993/08/25 14:00:05 ram |
| 23 | ?RCS: patch6: added ldflags as a conditional dependency and to compile line |
| 24 | ?RCS: patch6: a final double quote was missing in csym variable after eval |
| 25 | ?RCS: |
| 26 | ?RCS: Revision 3.0 1993/08/18 12:04:50 ram |
| 27 | ?RCS: Baseline for dist 3.0 netwide release. |
| 28 | ?RCS: |
| 29 | ?MAKE:Csym mistrustnm extern_C: Options contains libc libs runnm test \ |
| 30 | +cc +optimize +ccflags +ldflags run rm_try _exe d_cplusplus |
| 31 | ?MAKE: -pick add $@ %< |
| 32 | ?LINT:define csym |
| 33 | ?LINT:use libc |
| 34 | ?LINT:extern mistrustnm |
| 35 | ?LINT:set mistrustnm |
| 36 | ?S:csym: |
| 37 | ?S: This shell variable is used internally by Configure to check |
| 38 | ?S: whether a given C symbol is defined or not. A typical use is: |
| 39 | ?S: set symbol result [-fva] [previous] |
| 40 | ?S: eval $csym |
| 41 | ?S: That will set result to 'true' if the function [-f], variable [-v] |
| 42 | ?S: or array [-a] is defined, 'false' otherwise. If a previous value is |
| 43 | ?S: given and the -r flag was provided on the command line, that value |
| 44 | ?S: is reused without questioning. |
| 45 | ?S:. |
| 46 | ?S:extern_C: |
| 47 | ?S: ANSI C requires 'extern' where C++ requires 'extern "C"'. This |
| 48 | ?S: variable can be used in Configure to do the right thing. |
| 49 | ?S:. |
| 50 | ?S:mistrustnm: |
| 51 | ?S: This variable can be used to establish a fallthrough for the cases |
| 52 | ?S: where nm fails to find a symbol. If usenm is false or usenm is true |
| 53 | ?S: and mistrustnm is false, this variable has no effect. If usenm is true |
| 54 | ?S: and mistrustnm is "compile", a test program will be compiled to try to |
| 55 | ?S: find any symbol that can't be located via nm lookup. If mistrustnm is |
| 56 | ?S: "run", the test program will be run as well as being compiled. |
| 57 | ?S:. |
| 58 | ?V:csym |
| 59 | ?T:tval tx tlook tf tdc |
| 60 | ?F:!try |
| 61 | : is a C symbol defined? |
| 62 | csym='tlook=$1; |
| 63 | case "$3" in |
| 64 | -v) tf=libc.tmp; tdc="";; |
| 65 | -a) tf=libc.tmp; tdc="[]";; |
| 66 | *) tlook="^$1\$"; tf=libc.list; tdc="()";; |
| 67 | esac; |
| 68 | case "$d_cplusplus" in |
| 69 | $define) extern_C="extern \"C\"" ;; |
| 70 | *) extern_C="extern" ;; |
| 71 | esac; |
| 72 | tx=yes; |
| 73 | case "$reuseval-$4" in |
| 74 | true-) ;; |
| 75 | true-*) tx=no; eval "tval=\$$4"; case "$tval" in "") tx=yes;; esac;; |
| 76 | esac; |
| 77 | case "$tx" in |
| 78 | yes) |
| 79 | ?X: |
| 80 | ?X: Put symbol inside a printf to fool optimizing compilers... |
| 81 | ?X: |
| 82 | ?X: We use 'short' instead of 'int' to try to circumvent overzealous |
| 83 | ?X: optimizing compilers using built-in prototypes for commonly used |
| 84 | ?X: routines to complain when seeing a different external declaration. For |
| 85 | ?X: instance, gcc 2.6.3 fails if we use 'int' and we attempt a test against |
| 86 | ?X: memcpy() on machines where sizeof(int) == sizeof(char *) (the usual return |
| 87 | ?X: type), the compiler assuming it's a built-in declaration given that the |
| 88 | ?X: returned size matches. At least with 'short' we are safe! -- RAM, for ADO |
| 89 | ?X: |
| 90 | ?X: Let's thank GNU cc for making our lives so easy! :-) |
| 91 | ?X: (An alternative for the future would be to use our knowledge about gcc |
| 92 | ?X: to force a -fno-builtin option in the compile test, in case the 'short' |
| 93 | ?X: trick is obsoleted by future gcc releases). -- RAM |
| 94 | ?X: |
| 95 | tval=false; |
| 96 | if $test "$runnm" = true; then |
| 97 | if $contains $tlook $tf >/dev/null 2>&1; then |
| 98 | tval=true; |
| 99 | elif $test "$mistrustnm" = compile -o "$mistrustnm" = run; then |
| 100 | echo "$extern_C void *$1$tdc; void *(*(p()))$tdc { return &$1; } int main() { if(p()) return(0); else return(1); }"> try.c; |
| 101 | $cc -o try $optimize $ccflags $ldflags try.c >/dev/null 2>&1 $libs && tval=true; |
| 102 | $test "$mistrustnm" = run -a -x try && { $run ./try$_exe >/dev/null 2>&1 || tval=false; }; |
| 103 | $rm_try; |
| 104 | fi; |
| 105 | else |
| 106 | echo "$extern_C void *$1$tdc; void *(*(p()))$tdc { return &$1; } int main() { if(p()) return(0); else return(1); }"> try.c; |
| 107 | $cc -o try $optimize $ccflags $ldflags try.c $libs >/dev/null 2>&1 && tval=true; |
| 108 | $rm_try; |
| 109 | fi; |
| 110 | ;; |
| 111 | *) |
| 112 | case "$tval" in |
| 113 | $define) tval=true;; |
| 114 | *) tval=false;; |
| 115 | esac; |
| 116 | ;; |
| 117 | esac; |
| 118 | eval "$2=$tval"' |
| 119 | |