What is the meaning of "return ret < 0"?

Question

Functions can return a number, pointer, and most of the type you want, but what's the meaning of it?

return ret < 0;

(This code snippet is from the last line of the code, ffprobe.c.)

What part of that do you not understand? Do you know the "return" keyword in C? Do you know the comparison operator `<`? Do you recognize `ret` as a variable declared earlier? Put it all together.... — abelenky, Jan 07 '14 at 16:48

haccks · Accepted Answer · 2014-01-07T16:41:28.107

14

It will return either 1 or 0 depending upon the condition ret < 0 is true or false.

You can understand this as

if(ret < 0)
    return 1;
else  
    return 0;

edited Jan 07 '14 at 16:41

answered Jan 07 '14 at 16:35

haccks

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Aww edited to say half of what I said. At least it's more clear for the op. – uchuugaka Jan 07 '14 at 16:48
Before your answer I already had edited my answer but I became late because of my slow internet connection (Downloading a game *Injustice* :D) – haccks Jan 07 '14 at 16:54
Just a friendly jibe. Just happy it's clear. The kind of traditional C coding style is confusing for people new to it who've probably seem more explicit coding styles (in normal human reading terms) while the traditional C pedantic people would say it is explicit because they are used to reading code the hard way by order of evaluation. – uchuugaka Jan 08 '14 at 00:23
In other terms you can say: *Its a beauty of C* :) – haccks Jan 08 '14 at 02:52

score 2 · Answer 2 · answered Jan 07 '14 at 16:40

It returns the value of the conditional operation. ret < 0 It's C shorthand that you often see. C programmers are notoriously pedantic and do not write code that is obvious to the learner. It's equivalent to what might be written explicitly for mortals as

if ( ret < 0 ) { return true; } else { return false; }

KARTHIK BHAT · Answer 3 · 2014-01-07T17:01:55.357

return statement can have a expression. when a function is returning using a return statement it evaluates the expression first.

       return (expression);

expression can be any valid expression in C. after evaluation it returns whatever value is the output of the expression(assuming the return type matches or compiler will through an error ) in your case the statement will be like

      return (ret < 0);

depending on the value of ret either 1( if ret is less than 0) or 0(if ret is greater than 0) will be returned

What is the meaning of "return ret < 0"?

3 Answers3