Use snprintf() with separated input buffers in C

Asked Jan 25 '19 at 21:21

Active Jan 26 '19 at 06:26

Viewed 72 times

I try to outsource the input buffers of my snprintf() function:

So how to translate this working example:

struct ElementStruct {
    char element1[10];
    char element2[10];
}elementStruct;

char rxTxBuffer[30] = {0};

snprintf(rxTxBuffer, 30, "{ %s %s }", elementStruct.element1, elementStruct.element2);

To this not working example:

struct ElementStruct {
    char element1[10];
    char element2[10];
}elementStruct;

char rxTxBuffer[30] = {0};

char string[] = {"{ %s %s }"};
const char* restrict elements[] = {elementStruct.element1, elementStruct.element2};

snprintf(rxTxBuffer, 30 ,string, *elements);

edited Jan 25 '19 at 21:37

asked Jan 25 '19 at 21:21

PascalS

C doesn't allow argument spreading from an array. The closest you can get is `vsnprintf()`, but it use a `va_list` rather than an array; it's useful for writing your own `printf`-like functions that get variable numbers of arguments. – Barmar Jan 25 '19 at 21:29
See also https://stackoverflow.com/q/54366443/1848654. – melpomene Jan 25 '19 at 21:31
Thanks for your hints, but I'm searching for a solution in C – PascalS Jan 25 '19 at 21:37
... er, yes? What did you think we were talking about? – melpomene Jan 25 '19 at 21:42
Sorry, I thought vsnprintf() is only included in C++. – PascalS Jan 25 '19 at 21:49
Not a duplicate of the question it was closed as duplicate of. – R.. GitHub STOP HELPING ICE Jan 26 '19 at 06:26
Wow. Somebody really checks! – David C. Rankin Jan 26 '19 at 06:54
Why do yo want to do that? From looking at the two code snippets, the 2nd is even more typing. – alk Jan 26 '19 at 11:10
BTW this `char string[] = {"{ %s %s }"};` should be `char string[] = "{ %s %s }";`. – alk Jan 26 '19 at 11:13

Use snprintf() with separated input buffers in C

0 Answers0