snprintf vs. strcpy (etc.) in C

Question

For doing string concatenation, I\'ve been doing basic strcpy, strncpy of char* buffers. Then I learned about the snprintf and friends

Answer 1

For most purposes I doubt the difference between using strncpy and snprintf is measurable.

If there's any formatting involved I tend to stick to only snprintf rather than mixing in strncpy as well.

I find this helps code clarity, and means you can use the following idiom to keep track of where you are in the buffer (thus avoiding creating a Shlemiel the Painter algorithm):

char sBuffer[iBufferSize];
char* pCursor = sBuffer;

pCursor += snprintf(pCursor, sizeof(sBuffer) - (pCursor - sBuffer),  "some stuff\n");

for(int i = 0; i < 10; i++)
{
   pCursor += snprintf(pCursor, sizeof(sBuffer) - (pCursor - sBuffer),  " iter %d\n", i);
}

pCursor += snprintf(pCursor, sizeof(sBuffer) - (pCursor - sBuffer),  "into a string\n");