[Bug 1000414] New: snprintf returns a useless value when provided buffer is too small

[bugzilla-daemon at ecoscentric dot com]

https://bugzilla.ecoscentric.com/show_bug.cgi?id=1000414

           Summary: snprintf returns a useless value when provided buffer is
                    too small
           Product: eCos
           Version: CVS
          Platform: All
        OS/Version: All
            Status: UNCONFIRMED
          Severity: normal
          Priority: normal
         Component: C library
        AssignedTo: jifl@ecoscentric.com
        ReportedBy: nicolas.schodet@spidcom.com
         QAContact: ecos-bugs@sources.redhat.com


When the provided buffer is too small, ecos snprintf returns the number of
characters written, not the number of characters which would have been
written.

Given the following program:

#include <stdio.h>
int
main (void)
{
    char buf[6];
    printf ("short => %d\n",
            snprintf (buf, sizeof (buf) / sizeof (buf[0]), "short"));
    printf ("longer => %d\n",
            snprintf (buf, sizeof (buf) / sizeof (buf[0]), "longer"));
    return 0;
}

With GNU libc:

short => 5
longer => 6

With eCos libc:

short => 5
longer => 5

There is no way to know that the output was truncated.

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