The next C standard is established and it’s slowly being implemented. If you have the latest version of the C compiler installed on your system, you can take advantage of some of the fun and improved features of the C programming language.
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\nI plan on covering some C23 features over the next few Lessons. Some of the features are available when using the current C standard (C17), providing you employ a few workarounds.<\/p>\n
For example, C23 adds the reserved words bool<\/em>, true<\/em>, and false<\/em>.<\/p>\n The bool<\/em> keyword identifies a Boolean data type, which is a value of either one and zero.<\/p>\n The true<\/em> and false<\/em> keywords identify TRUE and FALSE values, where TRUE is any non-zero value and FALSE is zero. Yes, these are technically bool<\/em> constants.<\/p>\n These new keywords are a great addition to C, and something that other programming languages have naturally. As keywords, bool<\/em>, true<\/em>, and false <\/em>may cause some issues where older C code may use them as identifiers. Still, I still believe them to be a great and necessary addition to the language.<\/p>\n If you want to use these words in your code now, all just add the This code uses the bool<\/em> and true<\/em> keywords, though they’re defined in the If you remove the 1216b.c:5:2: error: use of undeclared identifier ‘bool’ But if you compile with C23 features activated, the code builds.<\/p>\n To get those C23 features, or at least some of them, ensure that you have the latest C compiler installed. On my system, I obtained the clang-15<\/em> update, which is the most recent stable release available for my distro. According to the LLVM website<\/a>, we may have to wait until clang-18<\/em> until most of the C23 features are implemented. Still, enough of these new C language features are available that you can try them out, as I did with the following code and clang-15<\/em>:<\/p>\n Yes, this is the same program as before, minus including the I need to type clang-15<\/strong> as the system version of clang<\/em> is mapped to clang-14<\/em>. (I could change it, but meh.) The -Wall<\/strong> switch activates all warnings. The -std=c2x<\/strong> switch directs the compiler to use the C23 standard, as much of it as is implemented.<\/p>\n The program builds with no warnings or errors, which tells me that for clang-15<\/em> and when using the In next week’s Lesson<\/a>, I describe how to write code that identifies the C23 compiler version and to implement code that takes advantage of some of its features.<\/p>\n","protected":false},"excerpt":{"rendered":" It’s the first major update to the C programming language in a long time. Continue reading stdbool.h<\/code> header<\/a> to your code, as shown in the following example.<\/p>\n2023_12_16-Lesson-a.c<\/a><\/h3>\n
\r\n#include <stdio.h>\r\n#include <stdbool.h>\r\n\r\nint main()\r\n{\r\n bool b = 1;\r\n\r\n if( b==true )\r\n puts(\"B is true\");\r\n else\r\n puts(\"B is false\");\r\n\r\n return(0);\r\n}<\/pre>\nstdbool.h<\/code> header file. As such, this code compiles under the current version of C. Here is the output:<\/p>\nB is true<\/code><\/p>\n#include<\/code> directive (or comment it out), the compiler generates some errors:<\/p>\n
\n bool b = 1;
\n ^
\n1216b.c:7:6: error: use of undeclared identifier ‘b’
\n if( b==true )
\n ^
\n1216b.c:7:9: error: use of undeclared identifier ‘true’
\n if( b==true )
\n ^
\n3 errors generated.<\/span><\/p>\n2023_12_16-Lesson-b.c<\/a><\/h3>\n
\r\n#include <stdio.h>\r\n\r\nint main()\r\n{\r\n bool b = 1;\r\n\r\n if( b==true )\r\n puts(\"B is true\");\r\n else\r\n puts(\"B is false\");\r\n\r\n return(0);\r\n}<\/pre>\nstdbool.h<\/code> header. I used the following command to build the program:<\/p>\nclang-15 -Wall -std=c2x 2023_12_16-Lesson-b.c<\/code><\/p>\n-std=c2x<\/code> switch, I can work with some C23 features. Here’s the output:<\/p>\nB is true<\/code><\/p>\n