use of buffers in sprintf and snprintf

On MS Windows, there's actually a limit of 255 characters, cf.
http://www.aroma-project.org/howtos/UseLongFilenamesOnWindows/
(disclaimer: I'm the author).  Note particularly the comment at the
end:

"Unfortunately it is not a solution to try to use relative instead of
absolute pathnames. The limitation is deep down in the file system
itself and it is the absolute pathname that counts."

Admittedly, it's been several years when I last looked into it, but at
the time when I wrote that I spent lots of time investigating it.

/Henrik

Cheers,
Simon

On May 29, 2019, at 11:49 AM, jing hua zhao <jinghuazhao at hotmail.com> wrote:

Dear R-developers,

I am struggling with packaging with sprintf and snprintf() as the following WARNINGS from gcc 9.x,

 hap_c.c:380:46: warning: ?%d? directive output may be truncated writing between 1 and 10 bytes into a region of size between 0 and 127 [-Wformat-truncation=]
 hap_c.c:392:46: warning: ?%d? directive output may be truncated writing between 1 and 10 bytes into a region of size between 0 and 127 [-Wformat-truncation=]

Essentially, I have

#define MAX_FILENAME_LEN 128
char of1name[MAX_FILENAME_LEN],of2name[MAX_FILENAME_LEN], tempname[MAX_FILENAME_LEN];

...

snprintf(tempname,sizeof(tempname),"%s.%d", of1name, j);

It looks I could get around with


#define MAX_FILENAME_LEN 128

#define MAX_FILENAME_LEN2 256

char of1name[MAX_FILENAME_LEN],of2name[MAX_FILENAME_LEN], tempname[MAX_FILENAME_LEN2];

...
snprintf(tempname,2*sizeof(tempname)+1,"%s.%d", of1name, j)

It looks a bit waste of resources to me.


Any idea will be greatly appreciated,



Jing Hua

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