what does "for( ; ; )" mean in C program

[bobby]

hello group,
what does for( ; ; ) mean in C program

Thanks

 

[Walter Roberson]

what does for( ; ; ) mean in C program

This is a loop.

Do no initializations.

Do not test any condition to see whether you should continue.

Do not do anything after the end of a loop before the beginning
of the next loop through.


In summary: for(; is another way of writing while (1)
which is an infinite loop (unless broken out of somewhere
in the middle.)

 

[bobby]

This is a loop.

Do no initializations.

Do not test any condition to see whether you should continue.

Do not do anything after the end of a loop before the beginning
of the next loop through.

In summary: for(; is another way of writing while (1)
which is an infinite loop (unless broken out of somewhere
in the middle.)

Thank a lot

 

[Martin Ambuhl]

hello group,
what does for( ; ; ) mean in C program

while (1)

 

[Kenny McCormack]

while (1)

I always thought it meant:

while(27)

I guess it depends on what part of town you're from.

 

[sid]

hello group,
what does for( ; ; ) mean in C program

Thanks

It also means for(;1;
A 'while()' loop is equivalent to 'for(;'

 

[Ben Pfaff]

A 'while()' loop is equivalent to 'for(;'

while() is not valid syntax. I think you mean that a while(1)
loop is equivalent to for(;.

 

[Tomás Ó hÉilidhe]

Ben Pfaff:

while() is not valid syntax. I think you mean that a while(1)
loop is equivalent to for(;.

But the extra-paranoid don't use it coz they don't want 1 to be evaluted
upon every iteration ;-)

 

[Harald van Dijk]

Ben Pfaff:

But the extra-paranoid don't use it coz they don't want 1 to be evaluted
upon every iteration ;-)

Some people avoid using while(1) because they have to deal with broken
tools that give warnings for while(1) that they don't give for for(;.
Splint is an example of this:

$ cat splint-is-weird.c
int main(void) {
while (1) {}
}
$ splint splint-is-weird.c
Splint 3.1.2 --- 03 Jan 2008

splint-is-weird.c: (in function main)
splint-is-weird.c:2:10: Test expression for while not boolean, type int: 1
Test expression type is not boolean or int. (Use -predboolint to inhibit
warning)

Finished checking --- 1 code warning

Personally, I'd rather get rid of such broken tools -- splint especially
considering I've dealt with perfectly legitimate C code causing assertion
failures in it -- but others may consider the tools useful enough to work
around their deficiencies.

 

[Michal Nazarewicz]

Some people avoid using while(1) because they have to deal with broken
tools that give warnings for while(1) that they don't give for for(;.

for(; is also one character shorter then while(1).

 

[Chris Thomasson]

for(; is also one character shorter then while(1).

:^)

 

[yeti]

I always thought it meant:

while(27)

I guess it depends on what part of town you're from.

nah .. its actually while(42)

 

[runner]

hello group,
what does for( ; ; ) mean in C program

Thanks

#define ever (;

for ever

 

[Keith Thompson]

#define ever (;

for ever

If your goal is to be cute, by all means go ahead and use that macro.

If your goal is to write understandable and maintainable C, please
don't.

 

[runner]

If your goal is to be cute, by all means go ahead and use that macro.

If your goal is to write understandable and maintainable C, please
don't.

I'm being cute, i don't need that macro. But it does its job in explaining
what happens when no expression is provided.

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