how to truncate a string based on buffer size.

[Nandu_77b]

Can any one help me to truncate the string based on the buffer size, for the below show scenario. main() { int size = 50; char errmsg [size]; get_last_error( errmsg, size ); cout<<errmsg; } get_last_error( char *errmsg, int bufsize ) { string sErrMsg; if ( sErrMsg.capacity() > bufsize ) { // here i want to truncate the string, so that the size of string will fit into "bufsize". Then copy the string to errmsg // strcpy( errmsg, sErrMsg.c_str() ); // how to truncate the string based on given buffersize // so that we can atlest copy the possible string to errmsg if not the whole string } else { strcpy( errmsg, sErrMsg.c_str() ); *errcode = nErrCode; } }

[David Crow]

Nandu_77b wrote:

// how to truncate the string based on given buffersize

How about the substr() method?

"Love people and use things, not love things and use people." - Unknown

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

[Nandu_77b]

Nandu_77b wrote: // how to truncate the string based on given buffersize How about the substr() method? substr() this fun will not take buffer size, it takes length of characters. I need to truncate based on buffer size. Please see my code which will give you clear idea. -Nandu

[CPallini]

What about strncpy [^]? :)

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[Nandu_77b]

strncpy() will also take char length not the buffersize. - Nandu

[Nandu_77b]

--strncpy() will also take char length not the buffersize. - Nandu

[CPallini]

Are you aware that, for ANSI strings, the char length and the buffer size (bytes) are basically the same? :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
[My articles]

[David Crow]

If the size of your buffer is 50, then you would extract characters 0-49.

"Love people and use things, not love things and use people." - Unknown

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

[Nandu_77b]

Yes you are correct, Thanks Nandu

[Joe Woodbury]

lstrcpynA(errmsg, bufsize); If using TCHAR, do: lstrcpyn(errmsg, bufsize / sizeof(TCHAR)); (lstrcpyn is a tiny bit more efficient than strncpy since it doesn't fill the rest of the buffer with zeros after completing the copy. With large buffers, this is generally a waste of cycles.)

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