A Common Cause of Many error C141 in Keil C51 That Passes in Other Compilers

I wrote a bubble sort algorithm. It compiled fine in VC and other compilers, but went crazy with errors in Keil C51.

Besides basic issues like missing parentheses, one more likely cause is:

== Variable Name Collides with a C51 Keyword ==

For example, I used data, which is a C51 reserved keyword:

data is a C51 reserved keyword — the highlighting is not obvious and easy to miss

And I defined an array named data, which caused a bunch of error messages like this:

Lots of error C141: syntax error near '[', easily mistaken for syntax mistakes

Simply rename the array to something else.

I posted these screenshots just to show how unfairly subtle Keil's keyword highlighting is — that's why I didn't catch it at first…

This article is dedicated to the 2 hours I wasted on this QAQQAQ

Memory type can be omitted when declaring variables; C51 will use the default memory type based on the compilation model

Overview of C51 supported base data types

C51 variables have four storage classes:

Used to declare the address of a Special Function Register (SFR) on the 8051.

Used to declare a bit variable that can only be 0 or 1.

Most of the keywords are fine, but data is really easy to use out of habit from other languages…