The process of opening, reading, writing, and closing files is basic C language stuff. For specific details about a file, the stat() function is used to fill a stat structure. Unfolded are the nitty-gritties about the file itself, such as its size, ownership, and up to four time-date stamps.
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Reader Chris pointed out a fun and common C language inconsistency in last week’s Lesson: The constant M_PI isn’t always available. It’s not defined as part of the C standard, which means your compiler may lack this handy shortcut, located in the math.h header file. What to do, what to do?
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Mathematic geeks of the world celebrate March 14 as “pi day.” The logic is that the date is 3/14, which are the first three digits of the value π, or 3.14159….∞
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Of all the C language keywords you don’t use, auto is probably the most memorable. That’s because it’s listed first among the canonical table of 32 C language keywords. Yet, in all the code you’ve written or seen, auto is seldom used if at all. So what does it do and is it even necessary?
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The topic of conversion characters, or printf() percent placeholders, is vast and confusing. Most programmers know the basics, but the details are so complex that some handy shortcuts are overlooked. One of those shortcuts is the * wildcard that sets width values.
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Plenty of C coders implemented boolean variables long before the C99 standard introduced the _Bool type. Programmers defined TRUE and FALSE constants, they used char or short variables as toggles, or they manipulated bits in a byte to simulate binary and boolean operations. With all that going on, you’d think adding a boolean variable type to C and calling it bool would have been a no-brainer. It wasn’t.
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One of the C language keywords added in the C99 update is _Bool. It’s an underscore keyword, which means it lacks the respect gained by the other keywords — even the useless ones like auto.
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