cond-cmp-numeric-ge.mk revision 1.1
11.1Srillig# $NetBSD: cond-cmp-numeric-ge.mk,v 1.1 2020/08/23 13:50:17 rillig Exp $ 21.1Srillig# 31.1Srillig# Tests for numeric comparisons with the >= operator in .if conditions. 41.1Srillig 51.1Srillig# When both sides are equal, the >= operator always yields true. 61.1Srillig.if 1 >= 1 71.1Srillig.else 81.1Srillig.error 91.1Srillig.endif 101.1Srillig 111.1Srillig# This comparison yields the same result, whether numeric or character-based. 121.1Srillig.if 1 >= 2 131.1Srillig.error 141.1Srillig.endif 151.1Srillig 161.1Srillig.if 2 >= 1 171.1Srillig.else 181.1Srillig.error 191.1Srillig.endif 201.1Srillig 211.1Srillig# If this comparison were character-based instead of numerical, the 221.1Srillig# 5 would be >= 14 since its first digit is greater. 231.1Srillig.if 5 >= 14 241.1Srillig.error 251.1Srillig.endif 261.1Srillig 271.1Srillig.if 14 >= 5 281.1Srillig.else 291.1Srillig.error 301.1Srillig.endif 311.1Srillig 321.1Srillig# Scientific notation is supported, as per strtod. 331.1Srillig.if 2e7 >= 1e8 341.1Srillig.error 351.1Srillig.endif 361.1Srillig 371.1Srillig.if 1e8 >= 2e7 381.1Srillig.else 391.1Srillig.error 401.1Srillig.endif 411.1Srillig 421.1Srillig# Floating pointer numbers can be compared as well. 431.1Srillig# This might be tempting to use for version numbers, but there are a few pitfalls. 441.1Srillig.if 3.141 >= 111.222 451.1Srillig.error 461.1Srillig.endif 471.1Srillig 481.1Srillig.if 111.222 >= 3.141 491.1Srillig.else 501.1Srillig.error 511.1Srillig.endif 521.1Srillig 531.1Srillig# When parsed as a version number, 3.30 is greater than 3.7. 541.1Srillig# Since make parses numbers as plain numbers, that leads to wrong results. 551.1Srillig# Numeric comparisons are not suited for comparing version number. 561.1Srillig.if 3.30 >= 3.7 571.1Srillig.error 581.1Srillig.endif 591.1Srillig 601.1Srillig.if 3.7 >= 3.30 611.1Srillig.else 621.1Srillig.error 631.1Srillig.endif 641.1Srillig 651.1Srillig# As of 2020-08-23, numeric comparison is implemented as parsing both sides 661.1Srillig# as double, and then performing a normal comparison. The range of double is 671.1Srillig# typically 16 or 17 significant digits, therefore these two numbers seem to 681.1Srillig# be equal. 691.1Srillig.if 1.000000000000000001 >= 1.000000000000000002 701.1Srillig.else 711.1Srillig.error 721.1Srillig.endif 731.1Srillig 741.1Srilligall: 751.1Srillig @:; 76