what about memset?

[Bill Cunningham]

When I want to clear memory space this is what I typically do myself,

char a[100];
int i;
for (i=0;i != 100;++i)
a[i]='\0';

Now with the function memset I could do the same thing and it would be
portable. But would it always work?

memset( a, '\0', sizeof a);

Bill

[Richard Heathfield]

Bill Cunningham said:

When I want to clear memory space this is what I typically do myself,

char a[100];
int i;
for (i=0;i != 100;++i)
a[i]='\0';

Now with the function memset I could do the same thing and it would be
portable. But would it always work?

memset( a, '\0', sizeof a);

Yes, for integer types (including char types).

If you only need to do it once, you can do this:

char a[100] = {0};

This is because of default initialisation rules for partial
initialisations .

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

[Bill Cunningham]

"Richard Heathfield" <rj*@see.sig.in validwrote in message
news:Mb******** *************** *******@bt.com. ..

If you only need to do it once, you can do this:

char a[100] = {0};

This is because of default initialisation rules for partial
initialisations .

So char a[100]={0}; sets all to zero? But that's not exactly \0 is it,
as far as C is concerned?

Bill

[Ian Collins]

Bill Cunningham wrote:

"Richard Heathfield" <rj*@see.sig.in validwrote in message
news:Mb******** *************** *******@bt.com. ..

>If you only need to do it once, you can do this:

char a[100] = {0};

This is because of default initialisation rules for partial
initialisation s.

So char a[100]={0}; sets all to zero? But that's not exactly \0 is it,
as far as C is concerned?

If that's the case, what is \0?

--
Ian Collins

[Bill Cunningham]

"Ian Collins" <ia******@hotma il.comwrote in message
news:6l******** *****@mid.indiv idual.net...

If that's the case, what is \0?

It's supposed to mean null in addition to the string terminator.

Bill

[Bill Cunningham]

"Ian Collins" <ia******@hotma il.comwrote in message
news:6l******** *****@mid.indiv idual.net...

If that's the case, what is \0?

When I set all elements of the a array to zero, zero is printed on my
screen 0. When I set all elements to \0 nothing is printed to my screen. No
characters are visible so I am assuming the null character is set.

Bill

[Ian Collins]

Bill Cunningham wrote:

"Ian Collins" <ia******@hotma il.comwrote in message
news:6l******** *****@mid.indiv idual.net...

>If that's the case, what is \0?

When I set all elements of the a array to zero, zero is printed on my
screen 0. When I set all elements to \0 nothing is printed to my screen. No
characters are visible so I am assuming the null character is set.

Set to 0 or '0'?

--
Ian Collins

[Ben Bacarisse]

"Bill Cunningham" <no****@nspam.i nvalidwrites:

"Ian Collins" <ia******@hotma il.comwrote in message
news:6l******** *****@mid.indiv idual.net...

>If that's the case, what is \0?

When I set all elements of the a array to zero, zero is printed on my
screen 0.

The best explanation for this is that you set the elements to '0' not
zero. '0' is some number (most likely 48) that represents a character
in the source character set used by your compiler.

When I set all elements to \0 nothing is printed to my screen. No
characters are visible so I am assuming the null character is set.

\0 is not a number in C so I presume you mean '\0'. '\0' is a integer
constant expression with value 0. '\0' is 0 in almost every way --
the only difference is the way they are written. 0x0 and 000 are
other ways to write the same thing.

--
Ben.

[Bill Cunningham]

"Ben Bacarisse" <be********@bsb .me.ukwrote in message
news:87******** ****@bsb.me.uk. ..

\0 is not a number in C so I presume you mean '\0'. '\0' is a integer
constant expression with value 0. '\0' is 0 in almost every way --
the only difference is the way they are written. 0x0 and 000 are
other ways to write the same thing.

I am pretty sure there's an ascii difference in '\0' that I use and '0'
which would print a bunch of zeros.

Bill

[Ian Collins]

Bill Cunningham wrote:

"Ben Bacarisse" <be********@bsb .me.ukwrote in message
news:87******** ****@bsb.me.uk. ..

>\0 is not a number in C so I presume you mean '\0'. '\0' is a integer
constant expression with value 0. '\0' is 0 in almost every way --
the only difference is the way they are written. 0x0 and 000 are
other ways to write the same thing.

I am pretty sure there's an ascii difference in '\0' that I use and '0'
which would print a bunch of zeros.

What part of '\0' == 0 and '0' != 0 don't you understand?

--
Ian Collins