1 1.1 christos Configure Internals 2 1.1 christos =================== 3 1.1 christos 4 1.1 christos [ note: this file uses markdown for formatting ] 5 1.1 christos 6 1.1 christos Intro 7 1.1 christos ----- 8 1.1 christos 9 1.1 christos This is a collection of notes that are hopefully of interest to those 10 1.1 christos who decide to dive into Configure and what it does. This is a living 11 1.1 christos document and anyone is encouraged to add to it and submit changes. 12 1.1 christos There's no claim for this document to be complete at any time, but it 13 1.1 christos will hopefully reach such a point in time. 14 1.1 christos 15 1.1 christos 16 1.1 christos ---------------------------------------------------------------------- 17 1.1 christos 18 1.1 christos Parsing build.info files, processing conditions 19 1.1 christos ----------------------------------------------- 20 1.1 christos 21 1.1 christos Processing conditions in build.info files is done with the help of a 22 1.1 christos condition stack that tell if a build.info should be processed or if it 23 1.1 christos should just be skipped over. The possible states of the stack top are 24 1.1 christos expressed in the following comment from Configure: 25 1.1 christos 26 1.1 christos # The top item of this stack has the following values 27 1.1 christos # -2 positive already run and we found ELSE (following ELSIF should fail) 28 1.1 christos # -1 positive already run (skip until ENDIF) 29 1.1 christos # 0 negatives so far (if we're at a condition, check it) 30 1.1 christos # 1 last was positive (don't skip lines until next ELSE, ELSIF or ENDIF) 31 1.1 christos # 2 positive ELSE (following ELSIF should fail) 32 1.1 christos 33 1.1 christos Ground rule is that non-condition lines are skipped over if the 34 1.1 christos stack top is > 0. Condition lines (IF, ELSIF, ELSE and ENDIF 35 1.1 christos statements) need to be processed either way to keep track of the skip 36 1.1 christos stack states, so they are a little more intricate. 37 1.1 christos 38 1.1 christos Instead of trying to describe in words, here are some example of what 39 1.1 christos the skip stack should look like after each line is processed: 40 1.1 christos 41 1.1 christos Example 1: 42 1.1 christos 43 1.1 christos | IF[1] | 1 | | 44 1.1 christos | ... whatever ... | | this line is processed | 45 1.1 christos | IF[1] | 1 1 | | 46 1.1 christos | ... whatever ... | | this line is processed | 47 1.1 christos | ELSIF[1] | 1 -1 | | 48 1.1 christos | ... whatever ... | | this line is skipped over | 49 1.1 christos | ELSE | 1 -2 | | 50 1.1 christos | ... whatever ... | | this line is skipped over | 51 1.1 christos | ENDIF | 1 | | 52 1.1 christos | ... whatever ... | | this line is processed | 53 1.1 christos | ELSIF[1] | -1 | | 54 1.1 christos | ... whatever ... | | this line is skipped over | 55 1.1 christos | IF[1] | -1 -1 | | 56 1.1 christos | ... whatever ... | | this line is skipped over | 57 1.1 christos | ELSIF[1] | -1 -1 | | 58 1.1 christos | ... whatever ... | | this line is skipped over | 59 1.1 christos | ELSE | -1 -2 | | 60 1.1 christos | ... whatever ... | | this line is skipped over | 61 1.1 christos | ENDIF | -1 | | 62 1.1 christos | ... whatever ... | | this line is skipped over | 63 1.1 christos | ENDIF | | | 64 1.1 christos 65 1.1 christos Example 2: 66 1.1 christos 67 1.1 christos | IF[0] | 0 | | 68 1.1 christos | ... whatever ... | | this line is skipped over | 69 1.1 christos | IF[1] | 0 -1 | | 70 1.1 christos | ... whatever ... | | this line is skipped over | 71 1.1 christos | ELSIF[1] | 0 -1 | | 72 1.1 christos | ... whatever ... | | this line is skipped over | 73 1.1 christos | ELSE | 0 -2 | | 74 1.1 christos | ... whatever ... | | this line is skipped over | 75 1.1 christos | ENDIF | 0 | | 76 1.1 christos | ... whatever ... | | this line is skipped over | 77 1.1 christos | ELSIF[1] | 1 | | 78 1.1 christos | ... whatever ... | | this line is processed | 79 1.1 christos | IF[1] | 1 1 | | 80 1.1 christos | ... whatever ... | | this line is processed | 81 1.1 christos | ELSIF[1] | 1 -1 | | 82 1.1 christos | ... whatever ... | | this line is skipped over | 83 1.1 christos | ELSE | 1 -2 | | 84 1.1 christos | ... whatever ... | | this line is skipped over | 85 1.1 christos | ENDIF | 1 | | 86 1.1 christos | ... whatever ... | | this line is processed | 87 1.1 christos | ENDIF | | | 88 1.1 christos 89 1.1 christos Example 3: 90 1.1 christos 91 1.1 christos | IF[0] | 0 | | 92 1.1 christos | ... whatever ... | | this line is skipped over | 93 1.1 christos | IF[0] | 0 -1 | | 94 1.1 christos | ... whatever ... | | this line is skipped over | 95 1.1 christos | ELSIF[1] | 0 -1 | | 96 1.1 christos | ... whatever ... | | this line is skipped over | 97 1.1 christos | ELSE | 0 -2 | | 98 1.1 christos | ... whatever ... | | this line is skipped over | 99 1.1 christos | ENDIF | 0 | | 100 1.1 christos | ... whatever ... | | this line is skipped over | 101 1.1 christos | ELSIF[1] | 1 | | 102 1.1 christos | ... whatever ... | | this line is processed | 103 1.1 christos | IF[0] | 1 0 | | 104 1.1 christos | ... whatever ... | | this line is skipped over | 105 1.1 christos | ELSIF[1] | 1 1 | | 106 1.1 christos | ... whatever ... | | this line is processed | 107 1.1 christos | ELSE | 1 -2 | | 108 1.1 christos | ... whatever ... | | this line is skipped over | 109 1.1 christos | ENDIF | 1 | | 110 1.1 christos | ... whatever ... | | this line is processed | 111 1.1 christos | ENDIF | | | 112 1.1 christos 113 1.1 christos Example 4: 114 1.1 christos 115 1.1 christos | IF[0] | 0 | | 116 1.1 christos | ... whatever ... | | this line is skipped over | 117 1.1 christos | IF[0] | 0 -1 | | 118 1.1 christos | ... whatever ... | | this line is skipped over | 119 1.1 christos | ELSIF[0] | 0 -1 | | 120 1.1 christos | ... whatever ... | | this line is skipped over | 121 1.1 christos | ELSE | 0 -2 | | 122 1.1 christos | ... whatever ... | | this line is skipped over | 123 1.1 christos | ENDIF | 0 | | 124 1.1 christos | ... whatever ... | | this line is skipped over | 125 1.1 christos | ELSIF[1] | 1 | | 126 1.1 christos | ... whatever ... | | this line is processed | 127 1.1 christos | IF[0] | 1 0 | | 128 1.1 christos | ... whatever ... | | this line is skipped over | 129 1.1 christos | ELSIF[0] | 1 0 | | 130 1.1 christos | ... whatever ... | | this line is skipped over | 131 1.1 christos | ELSE | 1 2 | | 132 1.1 christos | ... whatever ... | | this line is processed | 133 1.1 christos | ENDIF | 1 | | 134 1.1 christos | ... whatever ... | | this line is processed | 135 1.1 christos | ENDIF | | | 136 1.1 christos 137
Indexes created Wed Mar 25 00:23:37 UTC 2026