1*98875883SSimon J. Gerraty# $NetBSD: cond-cmp-numeric-ge.mk,v 1.3 2023/09/07 05:36:33 rillig Exp $ 22c3632d1SSimon J. Gerraty# 32c3632d1SSimon J. Gerraty# Tests for numeric comparisons with the >= operator in .if conditions. 42c3632d1SSimon J. Gerraty 52c3632d1SSimon J. Gerraty# When both sides are equal, the >= operator always yields true. 62c3632d1SSimon J. Gerraty.if 1 >= 1 72c3632d1SSimon J. Gerraty.else 82c3632d1SSimon J. Gerraty. error 92c3632d1SSimon J. Gerraty.endif 102c3632d1SSimon J. Gerraty 112c3632d1SSimon J. Gerraty# This comparison yields the same result, whether numeric or character-based. 122c3632d1SSimon J. Gerraty.if 1 >= 2 132c3632d1SSimon J. Gerraty. error 142c3632d1SSimon J. Gerraty.endif 152c3632d1SSimon J. Gerraty 162c3632d1SSimon J. Gerraty.if 2 >= 1 172c3632d1SSimon J. Gerraty.else 182c3632d1SSimon J. Gerraty. error 192c3632d1SSimon J. Gerraty.endif 202c3632d1SSimon J. Gerraty 212c3632d1SSimon J. Gerraty# If this comparison were character-based instead of numerical, the 222c3632d1SSimon J. Gerraty# 5 would be >= 14 since its first digit is greater. 232c3632d1SSimon J. Gerraty.if 5 >= 14 242c3632d1SSimon J. Gerraty. error 252c3632d1SSimon J. Gerraty.endif 262c3632d1SSimon J. Gerraty 272c3632d1SSimon J. Gerraty.if 14 >= 5 282c3632d1SSimon J. Gerraty.else 292c3632d1SSimon J. Gerraty. error 302c3632d1SSimon J. Gerraty.endif 312c3632d1SSimon J. Gerraty 322c3632d1SSimon J. Gerraty# Scientific notation is supported, as per strtod. 332c3632d1SSimon J. Gerraty.if 2e7 >= 1e8 342c3632d1SSimon J. Gerraty. error 352c3632d1SSimon J. Gerraty.endif 362c3632d1SSimon J. Gerraty 372c3632d1SSimon J. Gerraty.if 1e8 >= 2e7 382c3632d1SSimon J. Gerraty.else 392c3632d1SSimon J. Gerraty. error 402c3632d1SSimon J. Gerraty.endif 412c3632d1SSimon J. Gerraty 422c3632d1SSimon J. Gerraty# Floating pointer numbers can be compared as well. 432c3632d1SSimon J. Gerraty# This might be tempting to use for version numbers, but there are a few pitfalls. 442c3632d1SSimon J. Gerraty.if 3.141 >= 111.222 452c3632d1SSimon J. Gerraty. error 462c3632d1SSimon J. Gerraty.endif 472c3632d1SSimon J. Gerraty 482c3632d1SSimon J. Gerraty.if 111.222 >= 3.141 492c3632d1SSimon J. Gerraty.else 502c3632d1SSimon J. Gerraty. error 512c3632d1SSimon J. Gerraty.endif 522c3632d1SSimon J. Gerraty 532c3632d1SSimon J. Gerraty# When parsed as a version number, 3.30 is greater than 3.7. 542c3632d1SSimon J. Gerraty# Since make parses numbers as plain numbers, that leads to wrong results. 552c3632d1SSimon J. Gerraty# Numeric comparisons are not suited for comparing version number. 562c3632d1SSimon J. Gerraty.if 3.30 >= 3.7 572c3632d1SSimon J. Gerraty. error 582c3632d1SSimon J. Gerraty.endif 592c3632d1SSimon J. Gerraty 602c3632d1SSimon J. Gerraty.if 3.7 >= 3.30 612c3632d1SSimon J. Gerraty.else 622c3632d1SSimon J. Gerraty. error 632c3632d1SSimon J. Gerraty.endif 642c3632d1SSimon J. Gerraty 65*98875883SSimon J. Gerraty# Numeric comparison works by parsing both sides 662c3632d1SSimon J. Gerraty# as double, and then performing a normal comparison. The range of double is 672c3632d1SSimon J. Gerraty# typically 16 or 17 significant digits, therefore these two numbers seem to 682c3632d1SSimon J. Gerraty# be equal. 692c3632d1SSimon J. Gerraty.if 1.000000000000000001 >= 1.000000000000000002 702c3632d1SSimon J. Gerraty.else 712c3632d1SSimon J. Gerraty. error 722c3632d1SSimon J. Gerraty.endif 732c3632d1SSimon J. Gerraty 742c3632d1SSimon J. Gerratyall: 752c3632d1SSimon J. Gerraty @:; 76